Grant-based uplink transmission in unlicensed band

ABSTRACT

Methods and devices for grant-based uplink transmission in an unlicensed band are provided. Uplink grant messages are transmitted to electronic devices (EDs) in order to indicate time-frequency resources that are allocated to the EDs for uplink transmission in an unlicensed spectrum band. For a given ED, in the event that a first listen-before-talk (LBT) operation for the time-frequency resource allocated to the ED fails, the ED performs a second LBT operation within the allocated time-frequency resource at a start time based on a start point configuration within the allocated time-frequency resource. If the second LBT operation succeeds, the ED transmits an uplink transmission within a remaining portion of the allocated time-frequency resource that includes an activation signal to indicate a start of the uplink transmission, and uplink payload data.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/512,551 entitled “GRANT-BASED UPLINK TRANSMISSION INUNLICENSED BAND” filed May 30, 2017, the entire content of which isincorporated herein by reference.

FIELD

The present disclosure relates generally to wireless communications and,in particular, to grant-based uplink transmission in an unlicensed band.

BACKGROUND

In wireless communication systems, an electronic device (ED) such as auser equipment (UE) wirelessly communicates with a Transmission andReceive Point (TRP), termed “base station”, to send data to the EDand/or receive data from the ED. A wireless communication from an ED toa base station is referred to as an uplink communication. A wirelesscommunication from a base station to an ED is referred to as a downlinkcommunication.

Resources are required to perform uplink and downlink communications.For example, an ED may wirelessly transmit data to a base station in anuplink transmission at a particular frequency and during a particulartime slot. The frequency and time slot used is an example of a physicalcommunication resource.

In an LTE grant-based transmission, the required transmission controlparameters are typically communicated via a Physical Uplink ControlChannel (PUCCH) and/or Physical Downlink Control Channel (PDCCH). Thebase station is aware of the identity of the ED sending the uplinktransmission using the granted uplink resources, because the basestation specifically granted those uplink resources to that ED.

Some modes of communication may enable communications with an ED over anunlicensed spectrum band, or over different spectrum bands (e.g., anunlicensed spectrum band and a licensed spectrum band) of a wirelessnetwork. Given the scarcity and expense of bandwidth in the licensedspectrum, exploiting the vast and free-of-charge unlicensed spectrum tooffload at least some communication traffic is an approach that hasgarnered interest from mobile broadband (MBB) network operators. Forexample, in some cases uplink transmissions may be transmitted over anunlicensed spectrum band. Accordingly, efficient and fair mechanisms forgrant-based uplink transmissions in the unlicensed spectrum may bedesirable.

SUMMARY

According to a first aspect, the present disclosure provides a methodfor an Electronic Device (ED) in a wireless network. The methodaccording to the first aspect includes receiving an uplink grant messagefrom a base station, the uplink grant message indicating atime-frequency resource allocated to the ED for uplink transmission inan unlicensed spectrum band. The method according to the first aspectfurther includes performing a first listen-before-talk (LBT) operationfor the allocated time-frequency resource, and performing a second LBToperation within the allocated time-frequency resource.

In some embodiments of the method according to the first aspect of thepresent disclosure, the method further includes transmitting an uplinktransmission within a remaining portion of the allocated time-frequencyresource in response to the second LBT operation succeeding. In suchembodiments, the uplink transmission may include an activation signal toindicate a start of the uplink transmission and uplink payload data.

In some embodiments of the method according to the first aspect of thepresent disclosure, the second LBT operation is performed at a starttime based on a start point configuration within the allocated timefrequency resource.

In some embodiments of the method according to the first aspect of thepresent disclosure, the start point configuration indicates theconfiguration of a plurality of possible start points of uplinktransmission within a subframe.

In some embodiments of the method according to the first aspect of thepresent disclosure, each start point is either at an OFDM symbolboundary or midway between adjacent OFDM symbol boundaries, within theallocated time-frequency resource.

In some embodiments of the method according to the first aspect of thepresent disclosure, the method further includes receiving, from the basestation, information indicating the start point configuration.

In some embodiments of the method according to the first aspect of thepresent disclosure, the activation signal is a demodulation referencesignal (DMRS).

In some embodiments of the method according to the first aspect of thepresent disclosure, transmitting an uplink transmission within theremaining portion of the allocated time-frequency resource comprisestransmitting the uplink transmission with one or more blanking intervalswithin the remaining portion of the allocated time-frequency resourcebased on the start point configuration.

In some embodiments of the method according to the first aspect of thepresent disclosure, performing a second LBT operation within theallocated time-frequency resource comprises performing an LBT operationat each of a plurality of start times based on the start pointconfiguration until one of the LBT operations succeeds.

In some embodiments of the method according to the first aspect of thepresent disclosure, the second LBT operation is performed during one ormore orthogonal frequency division multiplexing (OFDM) symbol intervalsimmediately preceding a start point within the allocated time-frequencyresource.

In some embodiments of the method according to the first aspect of thepresent disclosure, the method further includes, in response to thesecond LBT operation succeeding, transmitting a reservation signalbetween the start point of uplink transmission and the closest OFDMsymbol boundary after the start point.

In some embodiments of the method according to the first aspect of thepresent disclosure, the reservation signal includes a cyclic prefixextension of the following OFDM symbol.

In some embodiments of the method according to the first aspect of thepresent disclosure, transmitting an uplink transmission within aremaining portion of the allocated time-frequency resource comprisestransmitting the activation signal at a start point that is part of apre-configured subset of possible start points within the allocatedtime-frequency resource.

In some embodiments of the method according to the first aspect of thepresent disclosure, the activation signal is selected by the ED fromamong a plurality of activation signals associated with the ED. In suchembodiments, the plurality of activation signals may include a firstactivation signal to indicate that uplink transmission started at astart point that preceded the start point at which the first activationsignal is transmitted, and a second activation signal to indicate thatuplink transmission started at or after the start point at which thefirst activation signal is transmitted.

In some embodiments of the method according to the first aspect of thepresent disclosure: the ED is allocated a subset of subcarriers of acomponent carrier (CC) bandwidth; the second LBT operation is a widebandLBT operation that is based on energy measured on all of the subcarriersof the CC bandwidth during one or more OFDM symbol intervals immediatelypreceding a start point within the allocated time-frequency resource;and transmitting the uplink transmission comprises transmitting theuplink transmission on the allocated subset of subcarriers within theremaining portion of the allocated time-frequency resource with one ormore blanking intervals based on the start point configuration.

In some embodiments of the method according to the first aspect of thepresent disclosure: the ED is allocated a subset of subcarriers of acomponent carrier (CC) bandwidth; the second LBT operation is anarrowband LBT operation that is based on energy measured on theallocated subset of subcarriers during one or more OFDM symbol intervalsimmediately preceding a start point within the allocated time-frequencyresource; and transmitting the uplink transmission comprisestransmitting the uplink transmission on the allocated subset ofsubcarriers within the remaining portion of the allocated time-frequencyresource.

In some embodiments of the method according to the first aspect of thepresent disclosure, the first LBT operation is a wideband LBT operationthat is based on energy measured on all of the subcarriers of the CCbandwidth during one or more OFDM symbol intervals immediately precedingor immediately after a sub-frame boundary of the time-frequencyresource.

In some embodiments of the method according to the first aspect of thepresent disclosure: the ED is allocated an interlace of a plurality ofsubsets of subcarriers of the CC bandwidth, the subsets of subcarriersof the interlace being distributed within the CC bandwidth; the secondLBT operation is one of a plurality of second LBT operations that arerespectively based on energy measured on a respective one of the subsetsof subcarriers of the CC bandwidth during one or more OFDM symbolintervals immediately preceding the start point within the allocatedtime-frequency resource; and transmitting the uplink transmissioncomprises transmitting, within the remaining portion of the allocatedtime-frequency resource, an uplink transmission on one or more of theallocated subsets of subcarriers for which the respective narrowband LBTprocedure was successful.

In some embodiments of the method according to the first aspect of thepresent disclosure: the ED is allocated a set of subcarriers of a firstcomponent carrier (CC) bandwidth; the first and second LBT operationsare based on energy measured on the allocated set of subcarriers of thefirst CC bandwidth; transmitting the uplink transmission comprisestransmitting a first uplink transmission on the allocated set ofsubcarriers of the first CC bandwidth within a first remaining portionof the allocated time-frequency resource; the ED is allocated a set ofsubcarriers of a second CC bandwidth that is non-overlapping with thefirst CC bandwidth. In such embodiments, the method may further includeperforming LBT operations that are based on energy measured on theallocated set of subcarriers of the second CC bandwidth at the same timethat the LBT operations that are based on energy measured on theallocated set of subcarriers of the first CC bandwidth are performed.

In some embodiments of the method according to the first aspect of thepresent disclosure, the method further includes: continuing to performLBT operations that are based on energy measured on the allocated set ofsubcarriers of the second CC bandwidth at subsequent start points withinthe allocated time-frequency resource after the second LBT operationbased on energy measured on the allocated set of subcarriers of thefirst CC bandwidth succeeds; and in response to one of the LBToperations that are based on energy measured on the allocated set ofsubcarriers of the first CC bandwidth succeeding, transmitting a seconduplink transmission on the allocated set of subcarriers of the second CCbandwidth within a second remaining portion of the allocatedtime-frequency resource. In such embodiments, the second uplinktransmission may include a second activation signal to indicate a startof the second uplink transmission, and second uplink payload data.

According to a first aspect, the present disclosure provides anElectronic Device (ED) that includes one or more processors; and anon-transitory computer readable storage medium storing programming forexecution by the one or more processors, the programming includinginstructions to: receive an uplink grant message from a base station,the uplink grant message indicating a time-frequency resource allocatedto the ED for uplink transmission in an unlicensed spectrum band;perform a first listen-before-talk (LBT) operation for the allocatedtime-frequency resource; and perform a second LBT operation within theallocated time-frequency resource.

In some embodiments of the ED according to the second aspect of thepresent disclosure, the programming further includes instructions to:perform the second LBT operation at a start time based on a start pointconfiguration within the allocated time-frequency resource; and inresponse to the second LBT operation succeeding, transmit an uplinktransmission within a remaining portion of the allocated time-frequencyresource, the uplink transmission comprising: an activation signal toindicate a start of the uplink transmission; and uplink payload data.

In some embodiments of the ED according to the second aspect of thepresent disclosure, the start point configuration indicates theconfiguration of a plurality of possible start points of uplinktransmission within a subframe.

In some embodiments of the ED according to the second aspect of thepresent disclosure, each start point is either at an OFDM symbolboundary or midway between adjacent OFDM symbol boundaries, within theallocated time-frequency resource.

In some embodiments of the ED according to the second aspect of thepresent disclosure, the instructions to perform a second LBT operationwithin the allocated time-frequency resource comprises instructions toperform an LBT operation at each of a plurality of start times based onthe start point configuration until one of the LBT operations succeeds.

In some embodiments of the ED according to the second aspect of thepresent disclosure, the instructions to transmit an uplink transmissionwithin a remaining portion of the allocated time-frequency resourcecomprises instructions to transmit the activation signal at a startpoint that is part of a pre-configured subset of possible start pointswithin the allocated time-frequency resource.

In some embodiments of the ED according to the second aspect of thepresent disclosure, the activation signal is selected by the ED fromamong a plurality of activation signals associated with the ED. In suchembodiments, the plurality of activation signals may include a firstactivation signal to indicate that uplink transmission started at astart point that preceded the start point at which the first activationsignal is transmitted, and a second activation signal to indicate thatuplink transmission started at or after the start point at which thefirst activation signal is transmitted.

In some embodiments of the ED according to the second aspect of thepresent disclosure: the ED is allocated a subset of subcarriers of acomponent carrier (CC) bandwidth; the second LBT operation is a widebandLBT operation that is based on energy measured on all of the subcarriersof the CC bandwidth during one or more OFDM symbol intervals immediatelypreceding a start point within the allocated time-frequency resource;and the instructions to transmit the uplink transmission comprisesinstructions to transmit the uplink transmission on the allocated subsetof subcarriers within the remaining portion of the allocatedtime-frequency resource with one or more blanking intervals based on thestart point configuration.

In some embodiments of the ED according to the second aspect of thepresent disclosure: the ED is allocated a subset of subcarriers of acomponent carrier (CC) bandwidth; the second LBT operation is anarrowband LBT operation that is based on energy measured on theallocated subset of subcarriers during one or more OFDM symbol intervalsimmediately preceding a start point within the allocated time-frequencyresource; and the instructions to transmit the uplink transmissioncomprises instructions to transmit the uplink transmission on theallocated subset of subcarriers within the remaining portion of theallocated time-frequency resource.

In some embodiments of the ED according to the second aspect of thepresent disclosure: the ED is allocated an interlace of a plurality ofsubsets of subcarriers of the CC bandwidth, the subsets of subcarriersof the interlace being distributed within the CC bandwidth; the secondLBT operation is one of a plurality of second LBT operations that arerespectively based on energy measured on a respective one of the subsetsof subcarriers of the CC bandwidth during one or more OFDM symbolintervals immediately preceding the start point within the allocatedtime-frequency resource; and the instructions to transmit the uplinktransmission comprises instructions to transmit, within the remainingportion of the allocated time-frequency resource, an uplink transmissionon one or more of the allocated subsets of subcarriers for which therespective narrowband LBT procedure was successful.

According to an aspect of the present disclosure, there is provided amethod for an Electronic Device (ED) in a wireless network, the methodcomprising:

receiving an uplink grant message from a base station, the uplink grantmessage indicating a time-frequency resource allocated to the ED foruplink transmission in an unlicensed spectrum band; after a firstlisten-before-talk (LBT) operation for the allocated time-frequencyresource fails, performing a second LBT operation within the allocatedtime-frequency resource at a start time based on a start pointconfiguration within the allocated time-frequency resource; in responseto the second LBT operation succeeding, transmitting an uplinktransmission within a remaining portion of the allocated time-frequencyresource, the uplink transmission comprising: an activation signal toindicate a start of the uplink transmission; and uplink payload data.

Embodiments of the above aspect of the present disclosure may includeany one or more of the following:

wherein the start point configuration indicates the configuration of aplurality of possible start points of uplink transmission within asubframe;

wherein each start point is either at an OFDM symbol boundary or midwaybetween adjacent OFDM symbol boundaries, within the allocatedtime-frequency resource;

further comprising receiving, from the base station, informationindicating the start point configuration;

wherein the activation signal is a demodulation reference signal (DMRS);

wherein transmitting an uplink transmission within the remaining portionof the allocated time-frequency resource comprises transmitting theuplink transmission with one or more blanking intervals within theremaining portion of the allocated time-frequency resource based on thestart point configuration;

wherein performing a second LBT operation within the allocatedtime-frequency resource comprises performing an LBT operation at each ofa plurality of start times based on the start point configuration untilone of the LBT operations succeeds;

wherein the second LBT operation is performed during one or moreorthogonal frequency division multiplexing (OFDM) symbol intervalsimmediately preceding a start point within the allocated time-frequencyresource;

further comprising, in response to the second LBT operation succeeding,transmitting a reservation signal between the start point of uplinktransmission and the closest OFDM symbol boundary after the start point;

wherein transmitting an uplink transmission within a remaining portionof the allocated time-frequency resource comprises transmitting theactivation signal at a start point that is part of a pre-configuredsubset of possible start points within the allocated time-frequencyresource;

wherein the pre-configured subset of possible start points includesevery second possible start point for uplink transmission within theallocated time-frequency resource;

-   -   wherein the activation signal is selected by the ED from among a        plurality of activation signals associated with the ED, the        plurality of activation signals comprising: a first activation        signal to indicate that uplink transmission started at a start        point that preceded the start point at which the first        activation signal is transmitted; and a second activation signal        to indicate that uplink transmission started at or after the        start point at which the first activation signal is transmitted;

wherein the ED configures a transport block size for the uplink payloaddata based on a size of the remaining portion of the allocatedtime-frequency resource;

wherein transmitting the uplink transmission comprises: using packetsegmentation to generate the uplink payload data based on the adjustedtransport block size;

wherein: uplink transmissions for different transport block sizescorresponding to different start points are generated in advance of thefirst possible start point of uplink transmission for the allocatedtime-frequency resource; and transmitting the uplink transmissioncomprises transmitting the uplink transmission for the transport blocksize corresponding to the start point of the uplink transmission;

wherein the ED uses rate matching or puncturing to fit a transport blockinto the remaining portion of the allocated time-frequency resourcewithout changing the transport block size;

wherein: the ED is allocated a subset of subcarriers of a componentcarrier (CC) bandwidth; the second LBT operation is a wideband LBToperation that is based on energy measured on all of the subcarriers ofthe CC bandwidth during one or more OFDM symbol intervals immediatelypreceding a start point within the allocated time-frequency resource;and transmitting the uplink transmission comprises transmitting theuplink transmission on the allocated subset of subcarriers within theremaining portion of the allocated time-frequency resource with one ormore blanking intervals based on the start point configuration;

wherein: the ED is allocated a subset of subcarriers of a componentcarrier (CC) bandwidth; the second LBT operation is a narrowband LBToperation that is based on energy measured on the allocated subset ofsubcarriers during one or more OFDM symbol intervals immediatelypreceding a start point within the allocated time-frequency resource;and transmitting the uplink transmission comprises transmitting theuplink transmission on the allocated subset of subcarriers within theremaining portion of the allocated time-frequency resource;

wherein the first LBT operation is a wideband LBT operation that isbased on energy measured on all of the subcarriers of the CC bandwidthduring one or more OFDM symbol intervals immediately preceding orimmediately after a sub-frame boundary of the time-frequency resource;

wherein the allocated subset of subcarriers correspond to thesubcarriers of a physical resource block (PRB) within the allocatedtime-frequency resource;

wherein transmitting an uplink transmission comprises transmitting theactivation signal and/or a demodulation reference signal on the firstone or more OFDM symbol intervals after start point within the remainingportion of the allocated time-frequency resource;

wherein transmitting an uplink transmission comprises: transmitting theactivation signal on the first one or more OFDM symbol intervals of afirst start point after the second LBT operation is successful; andtransmitting a demodulation reference signal on the last one or moreOFDM symbol intervals of a subframe at the end of the allocatedtime-frequency resource;

wherein the activation signal is sparse in the frequency domain;

wherein: the ED is allocated a set of subcarriers of a first componentcarrier (CC) bandwidth; the first and second LBT operations are based onenergy measured on the allocated set of subcarriers of the first CCbandwidth; transmitting the uplink transmission comprises transmitting afirst uplink transmission on the allocated set of subcarriers of thefirst CC bandwidth within a first remaining portion of the allocatedtime-frequency resource; the ED is allocated a set of subcarriers of asecond CC bandwidth that is non-overlapping with the first CC bandwidth;and the operations further comprises performing LBT operations that arebased on energy measured on the allocated set of subcarriers of thesecond CC bandwidth at the same time that the LBT operations that arebased on energy measured on the allocated set of subcarriers of thefirst CC bandwidth are performed;

further comprising: continuing to perform LBT operations that are basedon energy measured on the allocated set of subcarriers of the second CCbandwidth at subsequent start points within the allocated time-frequencyresource after the second LBT operation based on energy measured on theallocated set of subcarriers of the first CC bandwidth succeeds; and inresponse to one of the LBT operations that are based on energy measuredon the allocated set of subcarriers of the first CC bandwidthsucceeding, transmitting a second uplink transmission on the allocatedset of subcarriers of the second CC bandwidth within a second remainingportion of the allocated time-frequency resource, the second uplinktransmission comprising: a second activation signal to indicate a startof the second uplink transmission; and second uplink payload data;

wherein: there is a predefined mapping between code blocks of data andstart point within the allocated time-frequency resource; and the uplinkpayload data that is transmitted as part of the uplink transmissionincludes the code blocks of data that are mapped to start points withinthe remaining portion of the allocated time-frequency resource; andwherein: there is a predefined mapping between code blocks of data andstart points within the allocated time-frequency resource; and theuplink payload data that is transmitted as part of the uplinktransmission includes a sequence of code blocks of data starting withthe code block mapped to the first start point of the allocatedtime-frequency resource.

According to another aspect of the present disclosure, there is provideda UE configured to implement the method according to the above aspect ofthe present disclosure.

According to another aspect of the present disclosure, there is provideda method for a base station in a wireless network, the methodcomprising: transmitting a first uplink grant message for a firstelectronic device (ED), the first uplink grant message indicating atime-frequency resource allocated to the first ED for uplinktransmission in an unlicensed spectrum band; monitoring for detection ofan activation signal associated with the first ED at start times basedon a start point configuration within the allocated time-frequencyresource until either the activation signal associated with the first EDis detected or the allocated time-frequency resource ends, theactivation signal associated with the first ED indicating a start ofuplink transmission from the first ED; and in response to detecting theactivation signal associated with the first ED, decoding uplink payloaddata for the first ED received by the base station between the start ofuplink transmission from the first ED and the end of the allocatedtime-frequency resource.

Embodiments of the above aspect of the present disclosure may includeany one or more of the following:

wherein the start point configuration indicates the configuration of aplurality of start point within a subframe;

further comprising: pre-configuring the start point configuration at thebase station; and transmitting, from the base station, an informationmessage indicating the start point configuration;

wherein the activation signal is a demodulation reference signal (DMRS)associated with the first ED and the base station uses the DMRS todecode the uplink payload data for the first ED;

wherein decoding uplink payload data for the first ED comprises decodingthe uplink payload data taking into account one or more blankingintervals within the remaining portion of the allocated time-frequencyresource based on the mini-slot configuration wherein monitoring fordetection of the activation signal associated with the first EDcomprises monitoring for detection of the activation signal associatedwith the first ED starting at or after each of a plurality of startpoint within the allocated time-frequency resource until either theactivation signal associated with the first ED is detected or theallocated time-frequency resource ends;

wherein monitoring for detection of an activation signal associated withthe first ED comprises monitoring for detection of the activation signalat a pre-configured subset of the possible start points for uplinktransmission within the allocated time-frequency resource;

wherein the pre-configured subset of possible start points includesevery second possible start point for uplink transmission within theallocated time-frequency resource;

wherein monitoring for detection of an activation signal associated withthe first ED comprises monitoring for detection of a plurality ofactivation signals associated with the first ED, the plurality ofactivation signals comprising: a first activation signal to indicatethat uplink transmission started at a start point that preceded thestart point at which the first activation signal is transmitted; and asecond activation signal to indicate that uplink transmission started ator after the start point at which the first activation signal istransmitted;

wherein decoding the uplink payload data for the first ED in response todetecting the activation signal indicating the start of uplinktransmission from the first ED comprises: determining an expectedtransport block size for the uplink payload data based on a size of aremaining portion of the allocated time-frequency resource after thestart of uplink transmission from the first ED; and decoding the uplinkpayload data based in part on the expected transport block size;

wherein the base station determines the expected transport block sizebased on a mapping between transport block sizes and possible startpoints for uplink transmission within the allocated time-frequencyresource;

wherein decoding the uplink payload data takes into account ratematching or puncturing done by the first ED to fit a transport blockinto the remaining portion of the allocated time-frequency resource;

wherein: the first uplink grant message for the first ED indicates thefirst ED is allocated a first subset of subcarriers of a componentcarrier (CC) bandwidth within the time-frequency resource; monitoringfor detection of an activation signal associated with the first EDcomprises monitoring for the detection of the activation signalassociated with the first ED on the first subset of subcarriersallocated to the first ED; and decoding uplink payload data for thefirst ED in response to detecting the activation signal associated withthe first ED comprises decoding the uplink payload data for the first EDreceived by the base station on the first subset of subcarriersallocated to the first ED between the start of uplink transmission fromthe first ED and the end of the time-frequency resource;

further comprising: transmitting a second uplink grant message for asecond ED, the second uplink grant message indicating the second ED isallocated a second subset of subcarriers of the CC bandwidth within thetime-frequency resource for uplink transmission in the unlicensedspectrum band, the second subset of subcarriers being non-overlappingwith the first subset of subcarriers; monitoring for detection of anactivation signal associated with the second ED on the second subset ofsubcarriers at start times based on the start point configuration withinthe time-frequency resource until either the activation signalassociated with the second ED is detected or the time-frequency resourceends, the activation signal associated with the second ED indicting astart of uplink transmission from the second ED; and in response todetecting the activation signal associated with the second ED, decodinguplink payload data for the second ED received by the base station onthe second subset of subcarriers between the start of uplinktransmission from the second ED and the end of the time-frequencyresource;

wherein the allocated subsets of subcarriers correspond to thesubcarriers of first and second physical resource blocks (PRBs),respectively, within the time-frequency resource;

wherein the base station decodes the uplink payload data for the firstED based in part on a demodulation reference signal transmitted by thefirst ED as part of the uplink transmission on the first one or moreOFDM symbol intervals of each start point between the start of uplinktransmission from the first ED and the end of the allocatedtime-frequency resource;

wherein the base station decodes the uplink payload data for the firstED based in part on a demodulation reference signal transmitted by thefirst ED as part of the uplink transmission on the last one or more OFDMsymbol intervals of a subframe at the end of the allocatedtime-frequency resource;

wherein: the first uplink grant message for the first ED indicates thefirst ED is allocated first and second component carrier (CC) bandwidthswithin the time-frequency resource; monitoring for detection of anactivation signal associated with the first ED comprises: monitoring fordetection of a first activation signal associated with the first ED on aset of subcarriers of the first CC bandwidth, the first activationsignal indicating a start of first uplink transmission from the first EDon the set of subcarriers of the first CC bandwidth; and monitoring fordetection of a second activation signal associated with the first ED ona set of subcarriers of the second CC bandwidth, the second activationsignal indicating a start of second uplink transmission from the firstED on the set of subcarriers of the second CC bandwidth;

and decoding uplink payload data for the first ED in response todetecting the activation signal comprises at least one of: in responseto detecting the first activation signal associated with the first ED onthe set of subcarriers of the first CC bandwidth, decoding first uplinkpayload data for the first ED received by the base station on the set ofsubcarriers of the first CC bandwidth between the start of first uplinktransmission from the first ED and the end of the allocatedtime-frequency resource; and in response to detecting the secondactivation signal associated with the first ED on the set of subcarriersof the second CC bandwidth, decoding second uplink payload data for thefirst ED received by the base station on the set of subcarriers of thesecond CC bandwidth between the start of second uplink transmission fromthe first ED and the end of the allocated time-frequency resource;

further comprising: transmitting a second uplink grant message for asecond ED, the second uplink grant message indicating the second ED isallocated the set of subcarriers of the second CC bandwidth within thetime-frequency resource for uplink transmission in the unlicensedspectrum band; monitoring for detection of an activation signalassociated with the second ED on the set of subcarriers of the second CCbandwidth at start times based on the start point configuration withinthe time-frequency resource until either the activation signalassociated with the second ED is detected or the time-frequency resourceends, the activation signal associated with the second ED indicating astart of uplink transmission from the second ED; and in response todetecting the activation signal associated with the second ED, decodinguplink payload data for the second ED received by the base station onthe set of subcarriers of the second CC bandwidth between the start ofuplink transmission from the second ED and the end of the time-frequencyresource.

According to another aspect of the present disclosure, there is provideda base station configured to implement the method according to the aboveaspect of the present disclosure.

According to another aspect of the present disclosure, there is provideda non-transitory computer readable storage medium storing programmingfor execution by one or more processors, the programming includinginstructions to perform A method according to any one or more of theabove aspects of the present disclosure.

According to another aspect of the present disclosure, there is providedan Electronic Device (ED) comprising: one or more processors; and anon-transitory computer readable storage medium storing programming forexecution by the one or more processors, the programming includinginstructions to: in response to: i) receiving an uplink grant messagefrom a base station, the uplink grant message indicating atime-frequency resource allocated to the ED for uplink transmission inan unlicensed spectrum band; and ii) after a first listen-before-talk(LBT) operation for the allocated time-frequency resource fails, performa second LBT operation within the allocated time-frequency resource at astart time based on a start point configuration within the allocatedtime-frequency resource; and in response to the second LBT operationsucceeding, transmit an uplink transmission within a remaining portionof the allocated time-frequency resource, the uplink transmissioncomprising: an activation signal to indicate a start of the uplinktransmission; and uplink payload data.

According to another aspect of the present disclosure, there is provideda base station comprising: one or more processors; and a non-transitorycomputer readable storage medium storing programming for execution bythe one or more processors, the programming including instructions to:transmit a first uplink grant message for a first electronic device(ED), the first uplink grant message indicating a time-frequencyresource allocated to the first ED for uplink transmission in anunlicensed spectrum band; monitor for detection of an activation signalassociated with the first ED at start times based on a start pointconfiguration within the allocated time-frequency resource until eitherthe activation signal associated with the first ED is detected or theallocated time-frequency resource ends, the activation signal associatedwith the first ED indicating a start of uplink transmission from thefirst ED; and in response to detecting the activation signal associatedwith the first ED, decode uplink payload data for the first ED receivedby the base station between the start of uplink transmission from thefirst ED and the end of the allocated time-frequency resource.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure will be described in greaterdetail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a communication system.

FIGS. 2A, 2B and 2C are timing diagrams showing examples of anunlicensed spectrum band access procedure by an ED for grant-baseduplink transmission in accordance with an embodiment of the presentdisclosure.

FIGS. 3A and 3B are timing diagrams showing two examples of the timingof LBT operations relative to a mini-slot boundary in accordance with anembodiment of the present disclosure.

FIGS. 4A, 4B and 4C are timing diagrams showing examples of anunlicensed spectrum band access procedure by an ED for grant-baseduplink transmission that supports frequency domain multiplexing inaccordance with an embodiment of the present disclosure.

FIGS. 5A, 5B and 5C are timing diagrams showing examples of anunlicensed spectrum band access procedure by an ED for grant-baseduplink transmission that support uplink Multi-UserMultiple-Input-Multiple-Output in accordance with an embodiment of thepresent disclosure.

FIG. 6 is a timing diagram showing an example of an unlicensed spectrumband access procedure by an ED for grant-based uplink transmission thatsupports the scheduling of an ED on a time-frequency resource that spansone LBT bandwidth in the frequency domain in accordance with anembodiment of the present disclosure.

FIGS. 7A and 7B are timing diagrams showing two options for adapting theCBs that may be transmitted as part of the uplink transmission in thescenario depicted in FIG. 6.

FIG. 8 is a flow diagram of example operations in an ED according to anembodiment of the present disclosure.

FIG. 9 is a flow diagram of examples operations in a base station inaccordance with an embodiment of the present disclosure.

FIGS. 10A and 10B are block diagrams of an example ED and base station,respectively.

DETAILED DESCRIPTION

For illustrative purposes, specific example embodiments will now beexplained in greater detail below in conjunction with the figures.

The embodiments set forth herein represent information sufficient topractice the claimed subject matter and illustrate ways of practicingsuch subject matter. Upon reading the following description in light ofthe accompanying figures, those of skill in the art will understand theconcepts of the claimed subject matter and will recognize applicationsof these concepts not particularly addressed herein. It should beunderstood that these concepts and applications fall within the scope ofthe disclosure and the accompanying claims.

Moreover, it will be appreciated that any module, component, or devicedisclosed herein that executes instructions may include or otherwisehave access to a non-transitory computer/processor readable storagemedium or media for storage of information, such as computer/processorreadable instructions, data structures, program modules, and/or otherdata. A non-exhaustive list of examples of non-transitorycomputer/processor readable storage media includes magnetic cassettes,magnetic tape, magnetic disk storage or other magnetic storage devices,optical disks such as compact disc read-only memory (CD-ROM), digitalvideo discs or digital versatile discs (i.e. DVDs), Blu-Ray Disc™, orother optical storage, volatile and non-volatile, removable andnon-removable media implemented in any method or technology,random-access memory (RAM), read-only memory (ROM), electricallyerasable programmable read-only memory (EEPROM), flash memory or othermemory technology. Any such non-transitory computer/processor storagemedia may be part of a device or accessible or connectable thereto.Computer/processor readable/executable instructions to implement anapplication or module described herein may be stored or otherwise heldby such non-transitory computer/processor readable storage media.

As noted above, given the scarcity and expense of bandwidth in thelicensed spectrum, and the increasing demand for data transmissioncapacity, there is increasing interest in offloading at least somecommunication traffic, such as uplink communication traffic, to theunlicensed spectrum. However, when an uplink transmission from an ED toa base station takes place in the unlicensed spectrum, the ED mustperform a listen-before-talk (LBT) operation to make a clear channelassessment (CCA) before accessing the unlicensed spectrum in order tocheck that the channel is idle before transmitting. As such, even if abase station allocates a time-frequency resource in the unlicensedspectrum to an ED for uplink transmission, the ED may not be able tomake an uplink transmission using the allocated time-frequency resource.

For example, in an IEEE 802.11ax WLAN, which is a type of WLAN that wasdesigned to improve overall spectral efficiency particularly in densedeployment scenarios, an Access Point (AP) can schedule multiple EDs(referred to as stations (STAs) in IEEE 802.11ax) simultaneouslytransmitting in uplink either by Orthogonal Frequency Division MultipleAccess (OFDMA) or Multi-User Multiple-Input-Multiple-Output (MU MIMO).The scheduled STAs in IEEE 802.11ax perform LBT operations to make a CCAwithin the Short Inter-Frame Space (SIFS) after a trigger frame. If theCCA fails, a STA gives up the scheduled transmission opportunity (TXOP).

Similarly, in the 3rd Generation Partnership Project (3GPP) Long TermEvolution (LTE) specification for evolved Licensed Assisted Access(eLAA) in the unlicensed spectrum, an ED (referred to as User Equipment(UE) in LTE eLAA) that has received an uplink grant message indicatingthat the UE has been scheduled on a subframe for uplink transmission inthe unlicensed spectrum performs an LBT operation in the first OFDMsymbol interval of the scheduled subframe to make a CCA. If the CCA issuccessful (indicating that the channel is available), then the UE canproceed with transmitting uplink transmission from the starting pointindicated in the uplink grant. Otherwise, if the CCA fails (indicatingthat the channel is busy/unavailable), the UE gives up the wholesubframe. Thus the failure of the single LBT operation at the beginningof the subframe boundary of the scheduled subframe causes the UE towaste the whole subframe.

Systems and methods for grant-based uplink transmission in unlicensedspectrum are provided that may mitigate one or more of the disadvantagesof the approaches described above. For example, some aspects of thepresent disclosure provide mechanisms for EDs to perform LBT operationsand start uplink transmissions other than only at subframe boundaries.These mechanisms can provide multiple opportunities for scheduled UEs tocontend for a transmission opportunity within a time-frequency resourcethat they have been allocated for uplink transmission in the unlicensedspectrum. The multiple opportunities mean that the entire allocatedtime-frequency resource does not have to be wasted after a single failedLBT operation, which may reduce resource waste in unlicensed spectrumoperation.

Turning now to the figures, some specific example embodiments will bedescribed.

FIG. 1 illustrates an example communication system 100 in whichembodiments of the present disclosure could be implemented. In general,the communication system 100 enables multiple wireless or wired elementsto communicate data and other content. The purpose of the communicationsystem 100 may be to provide content (voice, data, video, text) viabroadcast, multicast, unicast, user device to user device, etc. Thecommunication system 100 may operate by sharing resources such asbandwidth.

In this example, the communication system 100 includes electronicdevices (ED) 110 a-110 c, radio access networks (RANs) 120 a-120 b, acore network 130, a public switched telephone network (PSTN) 140, theinternet 150, and other networks 160. Although certain numbers of thesecomponents or elements are shown in FIG. 1, any reasonable number ofthese components or elements may be included in the communication system100.

The EDs 110 a-110 c are configured to operate, communicate, or both, inthe communication system 100. For example, the EDs 110 a-110 c areconfigured to transmit, receive, or both via wireless or wiredcommunication channels. Each ED 110 a-110 c represents any suitable enduser device for wireless operation and may include such devices (or maybe referred to) as a user equipment/device (UE), wirelesstransmit/receive unit (WTRU), mobile station, fixed or mobile subscriberunit, cellular telephone, station (STA), machine type communication(MTC) device, personal digital assistant (PDA), smartphone, laptop,computer, tablet, wireless sensor, or consumer electronics device.

In FIG. 1, the RANs 120 a-120 b include base stations 170 a-170 b,respectively. Each base station 170 a-170 b is configured to wirelesslyinterface with one or more of the EDs 110 a-110 c to enable access toany other base station 170 a-170 b, the core network 130, the PSTN 140,the internet 150, and/or the other networks 160. For example, the basestations 170 a-170 b may include (or be) one or more of severalwell-known devices, such as a base transceiver station (BTS), a Node-B(NodeB), an evolved NodeB (eNodeB), a Home eNodeB, a gNodeB, atransmission and receive point (TRP), a site controller, an access point(AP), or a wireless router. Any ED 110 a-110 c may be alternatively oradditionally configured to interface, access, or communicate with anyother base station 170 a-170 b, the internet 150, the core network 130,the PSTN 140, the other networks 160, or any combination of thepreceding. The communication system 100 may include RANs, such as RAN120 b, wherein the corresponding base station 170 b accesses the corenetwork 130 via the internet 150, as shown.

The EDs 110 a-110 c and base stations 170 a-170 b are examples ofcommunication equipment that can be configured to implement some or allof the functionality and/or embodiments described herein. In theembodiment shown in FIG. 1, the base station 170 a forms part of the RAN120 a, which may include other base stations, base station controller(s)(BSC), radio network controller(s) (RNC), relay nodes, elements, and/ordevices. Any base station 170 a, 170 b may be a single element, asshown, or multiple elements, distributed in the corresponding RAN, orotherwise. Also, the base station 170 b forms part of the RAN 120 b,which may include other base stations, elements, and/or devices. Eachbase station 170 a-170 b transmits and/or receives wireless signalswithin a particular geographic region or area, sometimes referred to asa “cell” or “coverage area”. A cell may be further divided into cellsectors, and a base station 170 a-170 b may, for example, employmultiple transceivers to provide service to multiple sectors. In someembodiments there may be established pico or femto cells where the radioaccess technology supports such. In some embodiments, multipletransceivers could be used for each cell, for example usingmultiple-input multiple-output (MIMO) technology. The number of RAN 120a-120 b shown is exemplary only. Any number of RAN may be contemplatedwhen devising the communication system 100.

The base stations 170 a-170 b communicate with one or more of the EDs110 a-110 c over one or more air interfaces 190 using wirelesscommunication links e.g. radio frequency (RF), microwave, infrared (IR),etc. The air interfaces 190 may utilize any suitable radio accesstechnology. For example, the communication system 100 may implement oneor more orthogonal or non-orthogonal channel access methods, such ascode division multiple access (CDMA), time division multiple access(TDMA), frequency division multiple access (FDMA), orthogonal FDMA(OFDMA), or single-carrier FDMA (SC-FDMA) in the air interfaces 190.

A base station 170 a-170 b may implement Universal MobileTelecommunication System (UMTS) Terrestrial Radio Access (UTRA) toestablish an air interface 190 using wideband CDMA (WCDMA). In doing so,the base station 170 a-170 b may implement protocols such as HSPA, HSPA+optionally including HSDPA, HSUPA or both. Alternatively, a base station170 a-170 b may establish an air interface 190 with Evolved UTMSTerrestrial Radio Access (E-UTRA) using LTE, LTE-A, and/or LTE-B. It iscontemplated that the communication system 100 may use multiple channelaccess functionality, including such schemes as described above. Otherradio technologies for implementing air interfaces include IEEE 802.11,802.15, 802.16, CDMA2000, CDMA2000 1×, CDMA2000 EV-DO, IS-2000, IS-95,IS-856, GSM, EDGE, and GERAN. Of course, other multiple access schemesand wireless protocols may be utilized.

The RANs 120 a-120 b are in communication with the core network 130 toprovide the EDs 110 a-110 c with various services such as voice, data,and other services. The RANs 120 a-120 b and/or the core network 130 maybe in direct or indirect communication with one or more other RANs (notshown), which may or may not be directly served by core network 130, andmay or may not employ the same radio access technology as RAN 120 a, RAN120 b or both. The core network 130 may also serve as a gateway accessbetween (i) the RANs 120 a-120 b or EDs 110 a-110 c or both, and (ii)other networks (such as the PSTN 140, the internet 150, and the othernetworks 160). In addition, some or all of the EDs 110 a-110 c mayinclude functionality for communicating with different wireless networksover different wireless links using different wireless technologiesand/or protocols. Instead of wireless communication (or in additionthereto), the EDs may communicate via wired communication channels to aservice provider or switch (not shown), and to the internet 150. PSTN140 may include circuit switched telephone networks for providing plainold telephone service (POTS). Internet 150 may include a network ofcomputers and subnets (intranets) or both, and incorporate protocols,such as IP, TCP, UDP. EDs 110 a-110 c may be multimode devices capableof operation according to multiple radio access technologies, andincorporate multiple transceivers necessary to support such.

Embodiments of the present disclosure provide a grant-based transmissionmode for uplink transmissions in an unlicensed spectrum.

From the network perspective, a base station, such as an eNB or gNB, maypre-configure one or more start points within UL slot(s)/subframe(s).For example, the start points can include slot/subframe boundaries, anyOFDM symbol boundaries within the slot/subframe, or possibly pointsbetween OFDM symbol boundaries, as discussed in further detail belowwith reference to FIGS. 3A and 3B. The base station may then provide theone or more start points to EDs, e.g., via control signaling in thelicensed spectrum or unlicensed spectrum. The base station may thenallocate an uplink resource in the unlicensed spectrum to an ED in termsof slot(s)/subframe(s) in the time domain. For example, the base stationmay indicate the allocation to the ED by transmitting an uplink grantmessage to the ED. The base station may transmit such an uplink grantmessage in response to receiving an uplink scheduling request messagefrom the ED. As discussed in further detail below, EDs are configured totransmit an activation signal to indicate the start of uplinktransmission. The base station monitors for detection of potentialactivation signals from the scheduled ED at the min-slot andslot/subframe boundaries within the allocated resource until either thebase station successfully detects the activation signal associated withthe ED or the allocated resource has ended. If the base station detectsthe activation signal associated with a scheduled ED within theallocated resource, the base station attempts to decode the uplinkpayload data from the scheduled ED from transmissions received by thebase station between the start of uplink transmission from the scheduledED and the end of the allocated resource.

From the ED perspective, an ED may transmit an uplink scheduling requestto a base station. The uplink scheduling request may be transmitted overeither the licensed spectrum or unlicensed spectrum, for example. Inresponse to the uplink scheduling request, the ED may receive an uplinkgrant message from the base station indicating a time-frequency resourceallocated to the ED for uplink transmission in an unlicensed spectrumband. In some embodiments, the ED may also receive potential startpoint(s) from the base station. In other embodiments, the ED may havebeen previously configured with one or more start points. In response toreceiving the uplink grant message, the ED may perform an LBT operationat the potential start point(s) within the allocated resource based onthe configuration of potential start point(s). For example, if an LBToperation at a slot/subframe boundary fails, the ED may perform anotherLBT operation at the next start point within the slot/subframe. If theLBT operation at next start point fails, the ED may perform an LBToperation within one or more OFDM symbol intervals within the mini-slotand/or at the boundary of a subsequent mini-slot within theslot/subframe. The ED may continue to perform LBT operations atsubsequent times within the allocated resource until either an LBToperation is successful or the allocated resource has ended. If an LBToperation is successful, the ED transmits an uplink transmission withina remaining portion of the allocated resource. The uplink transmissionincludes an activation signal and uplink payload data. The activationsignal is transmitted by the ED to indicate the start of its uplinktransmission. The payload data may be transmitted before, after ortogether with the activation signal, as discussed in further detailbelow with reference to FIGS. 2A and 2B. In some embodiments, the ED mayreuse a demodulation reference signal (DMRS) within the allocatedresource as its activation signal. In general, the activation signal maybe any ED-specific signal to indicate the start of uplink transmissionto the base station. In some embodiments, the uplink transmissiontransmitted by the ED may be transmitted with one or more blankingintervals to avoid potential interference with the LBT operations ofother EDs, as discussed in further detail below.

FIGS. 2A and 2B are timing diagrams showing two examples of anunlicensed spectrum band access procedure by an ED to access anallocated time-frequency resource in an unlicensed spectrum band forgrant-based uplink transmission in accordance with an embodiment of thepresent disclosure. In particular, in FIG. 2A, a base station transmitsin downlink (DL) subframe # n an uplink (UL) grant for the uplinksubframe # n+k. The uplink subframe # n+k includes four start points#1-4. The ED performs an LBT operation at the boundary of subframe # n+k(which is also start point #1) and the start points #2 and #3. In thisexample, the LBT operation fails at the boundaries of subframe # n+k andstart point #2 and passes at the start point #3.

In response to the LBT operation at the start point #3 succeeding, theED begins transmitting an uplink transmission from start point #3. Theuplink transmission includes an activation signal to indicate the startof the uplink transmission, and uplink payload data. The activationsignal is transmitted within the unlicensed spectrum time-frequencyresource allocated to the ED. In some embodiments, the ED may transmit areservation signal (not shown in FIGS. 2A and 2B) within the allocatedtime-frequency resource between the end of the successful LBT and thetransmission of the activation signal. The reservation signal isintended to prevent other devices from accessing the time-frequencyresource the base station has allocated to the ED. For example, in someembodiments a cyclic prefix (CP) extension of a following OFDM symbol istransmitted as the reservation signal. Transmitting the CP extension ofthe following OFDM symbol as the reservation signal may also mitigateinter symbol interference.

The ED transmits the uplink transmission until the end of the allocatedresource. In some embodiments, the ED will adjust the transport block(TB) size used to transmit uplink traffic based on the amount of theallocated resource that remains after the successful LBT operation. Thetransmissions for different TB sizes corresponding to different startpoints can be prepared in advance in order to satisfy the short latencybetween the end of LBT and start of transmission. For example, if theLBT operation at the subframe boundary of subframe # n+k was successful,the ED may use a different TB size than if an LBT operation does notsucceed until the start point #3. In such embodiments, the base stationperforms a similar operation to configure an expected TB size to use indecoding the uplink payload data received from the ED. In someembodiments, the ED may use rate matching or puncturing to fit theoriginal TB into the accessible resource without changing the TB size.In some embodiments, the ED may use packet segmentation to generate theuplink payload data to fit within the remaining portion of the allocatedresource. The ED may transmit an updated buffer status report (BSR) aspart of the uplink transmission to advise the base station of itsupdated buffer status due to the packet segmentation.

In FIG. 2B, the base station can determine the start point of uplinktransmission from one or multiple pre-configured locations. If theuplink transmission starts from start points #1 or #2, the base stationwill detect an activation signal at the location of activation #1.Different sequences on the signals indicate whether the transmissionbegan at start point #1 or #2. The start point #3 and #4 are indicatedat the location of activation #2. The sequences are used to furtherdistinguish start points #3 and #4.

In the examples shown in FIGS. 2A and 2B, the LBT operations are shownas being within the OFDM symbol intervals that immediately precede thesubframe boundary and start points. More generally, as discussed infurther detail below with reference to FIGS. 3A-3B, LBT operations canoccupy one or more OFDM symbol intervals immediately beforesubframe/slot/mini-slot boundaries or one or more symbol intervalswithin the corresponding subframe/slot/mini-slot.

In some embodiments, an ED may be allocated an UL resource based on aninterlace of physical resource blocks (PRBs) distributed within achannel bandwidth. In such embodiments, an activation signal may betransmitted on each of the plurality of PRBs of the interlace allocatedto the ED. Regulations relating to unlicensed spectrum access mayrequire that transmissions made within a given channel bandwidth satisfya minimum occupancy channel bandwidth. By allocating an ED a pluralityof PRBs distributed within a channel bandwidth, it is possible tosatisfy the minimum occupancy channel bandwidth of such regulations.

FIG. 2C is a timing diagram showing an example of an unlicensed spectrumband access procedure by an ED to access a time-frequency resource in anunlicensed spectrum band for grant-based uplink transmission. Thetime-frequency resource allocated to the ED includes an interlace,Interlace #1, of PRBs.

As shown in FIG. 2C, an activation signal is transmitted by the ED onlyon the PRBs of the allocated interlace.

FIGS. 3A and 3B are timing diagrams showing two examples of the timingof LBT operations relative to start point in accordance with anembodiment of the present disclosure.

In FIG. 3A, the start point is at the OFDM symbol boundary. the LBToperation occupies time intervals immediately before the start point. Asnoted above, and shown in FIG. 3A, in some embodiments an ED may keepthe rest of symbol duration blank between the end of a successful LBToperation and the beginning of uplink transmission.

In FIG. 3B, rather than being at the OFDM symbol boundary, the startpoint is located at a point after the OFDM symbol boundary such that itis located between OFDM symbol boundaries. The LBT operation occupies anLBT time interval immediately before the start point. As shown in FIG.3B, the activation signal or DMRS starts at the first OFDM symbolboundary after the LBT operation passes at the start point. The ED maytransmit a reservation signal for the remainder of OFDM symbol (OS) OS#1 before starting uplink transmission in the second OS interval (OS #2)of the mini-slot. In some embodiments, the reservation signal may be aCP extension of the next OFDM symbol.

FIGS. 4A and 4B are timing diagrams showing examples of an unlicensedspectrum band access procedure by an ED for grant-based uplinktransmission that supports frequency domain multiplexing in accordancewith an embodiment of the present disclosure.

In FIG. 4A, frequency domain multiplexing of uplink transmissions fromdifferent EDs is supported by performing wideband LBT operations at thesubframe boundary and at potential start points within the subframe. Inthis example, two EDs (ED #1 and ED #2) are allocated non-overlappingphysical resource blocks (PRB #1 and PRB #2), virtual resource blocks orinterlaces. Each of the PRBs includes a respective subset of thesubcarriers of a component carrier (CC) bandwidth, e.g. a respectivesubset of the subcarriers within a 20 MHz CC bandwidth. An interlaceincludes multiple resource blocks distributed within the componentcarrier (CC) or bandwidth part (BWP). The bandwidth of CC or BWP can belarger than a unit bandwidth defined in the channelization, e.g. 20 MHz.The wideband LBT operations at the subframe boundary and potential startpoints within the subframe are based on energy measured on all of thesubcarriers of the CC bandwidth during the time period conforming toregulation. For example, the wideband LBT operations may measure theenergy of CC/system bandwidth according to the Category 2 (CAT2—LBTwithout random back-off) or Category 4 (CAT 4—LBT with random back-offwith variable size of contention window or extended CCA) LBT proceduresdefined for LTE license assisted access.

In FIG. 4A, after each ED completes a successful LBT operation andbegins uplink transmission, the ED transmits its uplink transmissionwith blanking intervals immediately before each of the subsequent startpoints in order to avoid having its uplink transmission act asinterference to the potential LBT operations of other EDs that may bescheduled in the same time-frequency resource. For example, the uplinktransmission transmitted by ED #2 after its successful LBT operation atthe boundary of subframe # n+k includes blanking intervals immediatelybefore the start points #2, #3 and #4.

In FIG. 4B, frequency domain multiplexing of uplink transmissions fromdifferent EDs is supported by performing a wideband LBT operation at aslot/subframe boundary and narrow band LBT operations at the startpoints within the duration of a slot or subframe. Similar to the exampleshown in FIG. 4A, in the example shown in FIG. 4B two EDs (ED #1 and ED#2) are allocated non-overlapping physical resource blocks (PRB #1 andPRB #2) that each include a respective subset of the subcarriers of a CCbandwidth. However, unlike the example shown in FIG. 4A, in the exampleshown in FIG. 4B the LBT operations that are performed immediatelybefore the start points #2, 3 and 4 within subframe # n+k are narrowbandLBT operations that are based on energy measured only on the respectivesubset of subcarriers allocated to the ED. The duration of a narrow bandLBT operation is equal to and aligned with one OFDM symbol interval.

In FIG. 4C, two EDs (ED #1 and ED #2) are allocated non-overlappinginterlaces (Interlace #1 and Interlace #2) that each include a pluralityof PRBs distributed within a CC or BWP. In the example shown in FIG. 4Cthe LBT operations that are performed immediately before the startpoints #2, 3 and 4 within subframe # n+k are narrowband LBT operationsthat are based on energy measured only on the respective PRBs of theinterlace allocated to the ED.

In FIGS. 4A, 4B and 4C, the wideband and narrowband LBT operations occurbefore the start points in the slot/subframe. The start point may startat the OFDM symbol boundary or in the middle of OFDM symbol duration.The term “wideband LBT” is used herein to refer to an LBT procedure inwhich an ED performs LBT on the channel bandwidth of a component carrieror bandwidth part in which the UL resource is scheduled, whereas theterm “narrowband LBT” is used herein to refer to an LBT procedure inwhich the bandwidth of the LBT performed by the ED is narrower than thefull channel bandwidth of a component carrier or bandwidth part in whichthe UL resource is scheduled, e.g., a bandwidth equal to the frequencyresource allocated to the ED.

In UL MU MIMO, multiple EDs may be scheduled on the same time-frequencyresource simultaneously. FIGS. 5A, 5B and 5C are timing diagrams showingexamples of an unlicensed spectrum band access procedure by an ED forgrant-based uplink transmission that supports UL MU MIMO in accordancewith an embodiment of the present disclosure. In these examples, two EDs(ED #1 and ED #2) are allocated the same time-frequency resource, andtheir respective uplink transmissions are distinguished by spatial layerseparation.

In FIG. 5A, UL MU MIMO is supported by reserving the first symbol(s) ofeach start point for DMRS and/or activation signal transmission for allEDs scheduled in the same time-frequency resource. For example, theuplink transmission transmitted by ED #2 after its successful LBToperation at the boundary of subframe # n+k includes ED #2's DMRS and/oractivation signal at the location of start points #1-4, which the basestation can potentially use to estimate the channel and decode uplinkdata in each mini-slot. This means that the base station can potentiallystart decoding ED #2's uplink payload data in each mini-slot as soon asit is received.

In FIG. 5B, UL MU MIMO is supported by reserving the pre-configuredsymbol interval(s) after the last start point in the subframe, e.g., thelast OS interval(s) of the subframe, for DMRS transmission. In thisexample, each UE transmits an activation signal at the beginning of itsuplink transmission and then transmits its DMRS in the last OS intervalsat the end of the subframe # n+k. For example, UE #2 transmits itsactivation signal in start point #1 after its successful LBT operationat the boundary of subframe # n+k, but does not transmit its DMRS untilthe last OS intervals at the end of subframe # n+k. Similarly, UE #1transmits its activation signal at start point #3 after its LBToperation succeeds, but does not transmit its DMRS until the last OSintervals at the end of subframe # n+k. This example saves signalingoverhead relative to the example shown in FIG. 5A (because the firstsymbol(s) of each mini-slot are not reserved for DMRS and/or activationsignal transmission), at the cost of potentially higher latency, becausethe base station has to wait until it receives the DMRS at the end ofthe subframe before it can decode the channel and the uplink data.

As shown in FIG. 5B, in some embodiments the activation signal can be a“lite” version that may be suitable for activation detection, but notfor channel estimation. For example, an activation signal may be sparsein the frequency domain, which is shown by way of example in theactivation signal transmitted by UE #1 at start point #3 in FIG. 5B.

In FIG. 5C, the positions of the activation signal and DMRS arepre-configured. For example, the possible positions are at the startpoint of #2 and #4. ED #2 starts uplink transmission from start point #1and will transmit DMRS at both locations, with the DMRS sequence atleast in first location indicating the uplink transmission starting atstart point #1. ED #1 starts uplink transmission from start point #3 andwill transmit DMRS at the second location with a DMRS sequenceindicating the start point #3. In this example, all DMRS sequences areorthogonal or have low cross correlation, which facilitates reliablechannel estimation across different spatial layers. In the embodiment,there is no additional activation signaling required. The use ofmultiple DMRSs can potentially provide better channel estimation inscenarios of higher mobility. In addition, the receiving latency issmaller than the case in FIG. 5B. A larger buffer size is requiredbecause the base station does not know exactly when the uplinktransmission starts until the DMRS symbol is detected.

In some cases, the time-frequency resource scheduled to an ED may beacross one LBT bandwidth in the frequency domain, e.g. multiple PRBsacross 20 MHz channel boundaries. FIG. 6 is a timing diagram showing anexample of an unlicensed spectrum band access procedure by an ED forgrant-based uplink transmission that supports the scheduling of an ED onsuch a time-frequency resource.

In FIG. 6, an ED is allocated a time-frequency resource that includes aset of subcarriers of a first 20 MHz CC bandwidth and a set ofsubcarriers of a second 20 MHz CC bandwidth. The ED performs LBToperations for the first 20 MHz CC bandwidth that are based on energymeasured on the allocated set of subcarriers of the first 20 MHz CCbandwidth and LBT operations for the second 20 MHz CC bandwidth that arebased on energy measured on the allocated set of subcarriers of thesecond 20 MHz CC bandwidth. The LBT operations are performed at thepotential start points in a slot/subframe. In FIG. 6, both of theinitial LBT operations for the first and second 20 MHz CC bandwidths atthe subframe boundary of subframe # n+k fail. The LBT operation for thesecond 20 MHz CC bandwidth at the start point #2 also fails. However,the LBT operation for the first 20 MHz CC bandwidth at the start point#2 succeeds, and the ED begins transmitting an uplink transmission on anallocated set of subcarriers of the first 20 MHz CC bandwidth at startpoint #2 and continues to do so until the end of the slot/subframe. Inthis example, the ED does not continue with further LBT operations forthe second 20 MHz CC bandwidth at the boundaries of start point #3 or #4once the LBT operation for the first 20 MHz CC bandwidth at the startpoint #2 succeeds. However, in other embodiments, the ED may continue toperform LBT operations for the second 20 MHz CC bandwidth at subsequentstart points within the allocated time-frequency resource even after anLBT operation for the first 20 MHz CC bandwidth succeeds. Furthermore,if a subsequent LBT operation for the second 20 MHz CC bandwidthsucceeds, the ED may begin transmitting an uplink transmission on theallocated subset of the second 20 MHz CC bandwidth within the portion ofthe allocated time-frequency resource that remains after the success ofthe LBT operation for the second 20 MHz CC bandwidth.

In some embodiments, a code block (CB) size may be adapted based on thetime-frequency resource size, in terms of frequency bandwidth and/ortime within the allocated time-frequency resource, that is available foruplink transmission. For example, referring again to FIG. 6, the CB sizemay be adapted to account for only half of the frequency bandwidth ofthe allocated time-frequency resource (i.e., only one of the two 20 MHzCC bandwidths) and only one interval between two consecutive startpoints (e.g. number of OFDM symbols between start point # n and startpoint # n+1). FIGS. 7A and 7B are timing diagrams showing two optionsfor adapting the CBs that may be transmitted as part of the uplinktransmission in the scenario depicted in FIG. 6.

In both FIGS. 7A and 7B, there is a predefined mapping between codeblocks of data and start points within the allocated time-frequencyresource. For example, code blocks CB(G) 11, CB(G) 12, CB(G) 13 andCB(G) 14 are mapped to start point #1, start point #2, start point #3and start point #4, respectively, on the allocated set of subcarriers ofthe first 20 MHz CC bandwidth. Similarly, code blocks CB(G) 21, CB(G)22, CB(G) 23 and CB(G) 24 are mapped to start point #1, start point #2,start point #3 and start point #4, respectively, on the allocated set ofsubcarriers of the second 20 MHz CC bandwidth.

In FIG. 7A, the uplink payload data that is transmitted as part of theuplink transmission that starts at start point #2 includes code blocksCB(G) 12, CB(G) 13 and CB(G) 14. These are the code blocks of data thatare mapped to the start points within the remaining portion of theallocated time-frequency resource after the LBT operation succeeds atstart point #2.

In contrast, in the second option shown in FIG. 7B, the uplink payloaddata this is transmitted as part of the uplink transmission includesCB(G) 11, CB(G) 12 and CB(G) 13. These are the code blocks of datastarting with the code block mapped to the first start point of theallocated time-frequency resource and continuing sequentially in thetime domain.

In both of these scenarios, the un-transmitted CB may be rescheduled orretransmitted automatically.

Various embodiments are described by way of example above. FIG. 8A is aflow diagram of example operations 800 in an ED according to anembodiment of the present disclosure.

At 802, the ED transmits an uplink scheduling request to a base station.At 804, the ED receives an uplink grant message from the base stationindicating that the ED has been allocated a time-frequency resource foruplink transmission in an unlicensed spectrum. At 806, the ED performs afirst LBT operation at a first start time based on a start pointconfiguration for the allocated time-frequency resource as discussedpreviously. At 808, if the first LBT is successful, the ED proceeds to816 (the Y path from 808), in which the ED transmits an uplinktransmission within a remaining portion of the allocated time-frequencyresource. The uplink transmission includes an activation signal anduplink payload data as discussed previously. If the first LBT at 808 isnot successful, the ED proceeds to 810 (the N path from 808), in whichthe ED performs a second LBT operation at a later start time based onthe start point configuration within the allocated time-frequencyresource. At 812, if the second LBT operation is successful, the EDproceeds to 816 (the Y path from 812) and transmits an uplinktransmission within the remaining portion of the allocatedtime-frequency resource. If the second LBT at 812 is not successful, theED proceeds to 814 (the N path from 812), in which the ED checks if thetime-frequency resource has ended. This may involve, for example,checking if the start point configuration indicates that there is stillat least one possible start point for uplink transmission remaining inthe allocated time-frequency resource. If there are no possible startpoints left for uplink transmission, the ED may return to 802 (the Ypath from 814) to transmit another uplink scheduling request. If thereis still at least one possible start point left for uplink transmission,the ED may return to 810 to perform another LBT operation at a laterstart time based on the start point configuration. In this way, if thefirst LBT operation at 808 fails, the ED may continue to loop throughsteps 810, 812 and 814 until either the time-frequency resource hasended or one of the LBT operations at 812 is successful and the ED isable to transmit an uplink transmission at 816.

Other variations of the example operations 800 could include performingthe illustrated operations in any of various ways and/or performingadditional or fewer operations.

For example, variations of the example operations 800 could include anyor all of the following:

wherein the start point configuration indicates the configuration of aplurality of possible start points of uplink transmission within asubframe;

wherein each start point is either at an OFDM symbol boundary or midwaybetween adjacent OFDM symbol boundaries, within the allocatedtime-frequency resource;

further comprising receiving, from the base station, informationindicating the start point configuration;

wherein the activation signal is a demodulation reference signal (DMRS);

wherein transmitting an uplink transmission within the remaining portionof the allocated time-frequency resource comprises transmitting theuplink transmission with one or more blanking intervals within theremaining portion of the allocated time-frequency resource based on thestart point configuration;

wherein performing a second LBT operation within the allocatedtime-frequency resource comprises performing an LBT operation at each ofa plurality of start times based on the start point configuration untilone of the LBT operations succeeds;

wherein the second LBT operation is performed during one or moreorthogonal frequency division multiplexing (OFDM) symbol intervalsimmediately preceding a start point within the allocated time-frequencyresource;

further comprising, in response to the second LBT operation succeeding,transmitting a reservation signal between the start point of uplinktransmission and the closest OFDM symbol boundary after the start point;

wherein transmitting an uplink transmission within a remaining portionof the allocated time-frequency resource comprises transmitting theactivation signal at a start point that is part of a pre-configuredsubset of possible start points within the allocated time-frequencyresource;

wherein the pre-configured subset of possible start points includesevery second possible start point for uplink transmission within theallocated time-frequency resource;

wherein the activation signal is selected by the ED from among aplurality of activation signals associated with the ED, the plurality ofactivation signals comprising: a first activation signal to indicatethat uplink transmission started at a start point that preceded thestart point at which the first activation signal is transmitted; and asecond activation signal to indicate that uplink transmission started ator after the start point at which the first activation signal istransmitted;

wherein the ED configures a transport block size for the uplink payloaddata based on a size of the remaining portion of the allocatedtime-frequency resource;

wherein transmitting the uplink transmission comprises: using packetsegmentation to generate the uplink payload data based on the adjustedtransport block size;

wherein: uplink transmissions for different transport block sizescorresponding to different start points are generated in advance of thefirst possible start point of uplink transmission for the allocatedtime-frequency resource; and transmitting the uplink transmissioncomprises transmitting the uplink transmission for the transport blocksize corresponding to the start point of the uplink transmission;

wherein the ED uses rate matching or puncturing to fit a transport blockinto the remaining portion of the allocated time-frequency resourcewithout changing the transport block size;

wherein: the ED is allocated a subset of subcarriers of a componentcarrier (CC) bandwidth; the second LBT operation is a wideband LBToperation that is based on energy measured on all of the subcarriers ofthe CC bandwidth during one or more OFDM symbol intervals immediatelypreceding a start point within the allocated time-frequency resource;and transmitting the uplink transmission comprises transmitting theuplink transmission on the allocated subset of subcarriers within theremaining portion of the allocated time-frequency resource with one ormore blanking intervals based on the start point configuration;

wherein: the ED is allocated a subset of subcarriers of a componentcarrier (CC) bandwidth; the second LBT operation is a narrowband LBToperation that is based on energy measured on the allocated subset ofsubcarriers during one or more OFDM symbol intervals immediatelypreceding a start point within the allocated time-frequency resource;and transmitting the uplink transmission comprises transmitting theuplink transmission on the allocated subset of subcarriers within theremaining portion of the allocated time-frequency resource;

wherein the first LBT operation is a wideband LBT operation that isbased on energy measured on all of the subcarriers of the CC bandwidthduring one or more OFDM symbol intervals immediately preceding orimmediately after a sub-frame boundary of the time-frequency resource;

wherein the allocated subset of subcarriers correspond to thesubcarriers of a physical resource block (PRB) within the allocatedtime-frequency resource;

wherein transmitting an uplink transmission comprises transmitting theactivation signal and/or a demodulation reference signal on the firstone or more OFDM symbol intervals after start point within the remainingportion of the allocated time-frequency resource;

wherein transmitting an uplink transmission comprises: transmitting theactivation signal on the first one or more OFDM symbol intervals of afirst start point after the second LBT operation is successful; andtransmitting a demodulation reference signal on the last one or moreOFDM symbol intervals of a subframe at the end of the allocatedtime-frequency resource;

wherein the activation signal is sparse in the frequency domain;

wherein: the ED is allocated a set of subcarriers of a first componentcarrier (CC) bandwidth; the first and second LBT operations are based onenergy measured on the allocated set of subcarriers of the first CCbandwidth; transmitting the uplink transmission comprises transmitting afirst uplink transmission on the allocated set of subcarriers of thefirst CC bandwidth within a first remaining portion of the allocatedtime-frequency resource; the ED is allocated a set of subcarriers of asecond CC bandwidth that is non-overlapping with the first CC bandwidth;and the operations further comprises performing LBT operations that arebased on energy measured on the allocated set of subcarriers of thesecond CC bandwidth at the same time that the LBT operations that arebased on energy measured on the allocated set of subcarriers of thefirst CC bandwidth are performed;

further comprising: continuing to perform LBT operations that are basedon energy measured on the allocated set of subcarriers of the second CCbandwidth at subsequent start points within the allocated time-frequencyresource after the second LBT operation based on energy measured on theallocated set of subcarriers of the first CC bandwidth succeeds; and inresponse to one of the LBT operations that are based on energy measuredon the allocated set of subcarriers of the first CC bandwidthsucceeding, transmitting a second uplink transmission on the allocatedset of subcarriers of the second CC bandwidth within a second remainingportion of the allocated time-frequency resource, the second uplinktransmission comprising: a second activation signal to indicate a startof the second uplink transmission; and second uplink payload data;

wherein: there is a predefined mapping between code blocks of data andstart point within the allocated time-frequency resource; and the uplinkpayload data that is transmitted as part of the uplink transmissionincludes the code blocks of data that are mapped to start points withinthe remaining portion of the allocated time-frequency resource;

wherein: there is a predefined mapping between code blocks of data andstart points within the allocated time-frequency resource; and theuplink payload data that is transmitted as part of the uplinktransmission includes a sequence of code blocks of data starting withthe code block mapped to the first start point of the allocatedtime-frequency resource.

FIG. 9 is a flow diagram of example operations 900 in a base stationaccording to an embodiment of the present disclosure.

At 902, the base station receives an uplink scheduling request from afirst ED. At 904, the base station transmits a first uplink grantmessage for the first ED, the first uplink grant message indicating atime-frequency resource allocated to the first ED for uplinktransmission in an unlicensed spectrum band. At 906, the base stationmonitors for detection of an activation signal associated with the firstED at start times based on a start point configuration within theallocated time-frequency resource. If an activation signal associatedwith the first ED is detected at 906, the base station proceeds to 910(the Y path from 906), in which the base station decodes uplink payloaddata for the first ED that was received between the start of uplinktransmission from the first ED and the end of the allocatedtime-frequency resource. If an activation signal associated with thefirst ED is not detected at 906, the base station proceeds to 908, inwhich the base station checks if the time-frequency resource has ended,e.g., if the start point configuration indicates that no further startpoints for uplink transmission remain in the allocated time-frequencyresource. If the time-frequency resource has ended, the base station mayreturn to the start and await a further uplink scheduling request fromthe first ED (the Y path from 908). If the time-frequency resource hasnot yet ended, such that at least one possible start point for uplinktransmission remains within the allocated time-frequency resource, thenthe base station may return to 906 (the N path from 908) to continue tomonitor for detection of an activation signal associated with the firstED. In this way, the base station may continue to monitor for theactivation signal until either the activation signal associated with thefirst ED is detected or the allocated time-frequency resource ends.

Other variations of the example operations 900 could include performingthe illustrated operations in any of various ways and/or performingadditional or fewer operations.

For example, variations of the example operations 900 could include anyor all of the following:

wherein the start point configuration indicates the configuration of aplurality of start point within a subframe;

further comprising: pre-configuring the start point configuration at thebase station; and transmitting, from the base station, an informationmessage indicating the start point configuration;

wherein the activation signal is a demodulation reference signal (DMRS)associated with the first ED and the base station uses the DMRS todecode the uplink payload data for the first ED;

wherein decoding uplink payload data for the first ED comprises decodingthe uplink payload data taking into account one or more blankingintervals within the remaining portion of the allocated time-frequencyresource based on the mini-slot configuration

wherein monitoring for detection of the activation signal associatedwith the first ED comprises monitoring for detection of the activationsignal associated with the first ED starting at or after each of aplurality of start point within the allocated time-frequency resourceuntil either the activation signal associated with the first ED isdetected or the allocated time-frequency resource ends;

wherein monitoring for detection of an activation signal associated withthe first ED comprises monitoring for detection of the activation signalat a pre-configured subset of the possible start points for uplinktransmission within the allocated time-frequency resource;

wherein the pre-configured subset of possible start points includesevery second possible start point for uplink transmission within theallocated time-frequency resource;

wherein monitoring for detection of an activation signal associated withthe first ED comprises monitoring for detection of a plurality ofactivation signals associated with the first ED, the plurality ofactivation signals comprising: a first activation signal to indicatethat uplink transmission started at a start point that preceded thestart point at which the first activation signal is transmitted; and asecond activation signal to indicate that uplink transmission started ator after the start point at which the first activation signal istransmitted;

wherein decoding the uplink payload data for the first ED in response todetecting the activation signal indicating the start of uplinktransmission from the first ED comprises: determining an expectedtransport block size for the uplink payload data based on a size of aremaining portion of the allocated time-frequency resource after thestart of uplink transmission from the first ED; and decoding the uplinkpayload data based in part on the expected transport block size;

wherein the base station determines the expected transport block sizebased on a mapping between transport block sizes and possible startpoints for uplink transmission within the allocated time-frequencyresource;

wherein decoding the uplink payload data takes into account ratematching or puncturing done by the first ED to fit a transport blockinto the remaining portion of the allocated time-frequency resource;

wherein: the first uplink grant message for the first ED indicates thefirst ED is allocated a first subset of subcarriers of a componentcarrier (CC) bandwidth within the time-frequency resource; monitoringfor detection of an activation signal associated with the first EDcomprises monitoring for the detection of the activation signalassociated with the first ED on the first subset of subcarriersallocated to the first ED; and decoding uplink payload data for thefirst ED in response to detecting the activation signal associated withthe first ED comprises decoding the uplink payload data for the first EDreceived by the base station on the first subset of subcarriersallocated to the first ED between the start of uplink transmission fromthe first ED and the end of the time-frequency resource;

further comprising: transmitting a second uplink grant message for asecond ED, the second uplink grant message indicating the second ED isallocated a second subset of subcarriers of the CC bandwidth within thetime-frequency resource for uplink transmission in the unlicensedspectrum band, the second subset of subcarriers being non-overlappingwith the first subset of subcarriers; monitoring for detection of anactivation signal associated with the second ED on the second subset ofsubcarriers at start times based on the start point configuration withinthe time-frequency resource until either the activation signalassociated with the second ED is detected or the time-frequency resourceends, the activation signal associated with the second ED indicting astart of uplink transmission from the second ED; and in response todetecting the activation signal associated with the second ED, decodinguplink payload data for the second ED received by the base station onthe second subset of subcarriers between the start of uplinktransmission from the second ED and the end of the time-frequencyresource;

wherein the allocated subsets of subcarriers correspond to thesubcarriers of first and second physical resource blocks (PRBs),respectively, within the time-frequency resource;

wherein the base station decodes the uplink payload data for the firstED based in part on a demodulation reference signal transmitted by thefirst ED as part of the uplink transmission on the first one or moreOFDM symbol intervals of each start point between the start of uplinktransmission from the first ED and the end of the allocatedtime-frequency resource;

wherein the base station decodes the uplink payload data for the firstED based in part on a demodulation reference signal transmitted by thefirst ED as part of the uplink transmission on the last one or more OFDMsymbol intervals of a subframe at the end of the allocatedtime-frequency resource;

wherein: the first uplink grant message for the first ED indicates thefirst ED is allocated first and second component carrier (CC) bandwidthswithin the time-frequency resource; monitoring for detection of anactivation signal associated with the first ED comprises: monitoring fordetection of a first activation signal associated with the first ED on aset of subcarriers of the first CC bandwidth, the first activationsignal indicating a start of first uplink transmission from the first EDon the set of subcarriers of the first CC bandwidth; and monitoring fordetection of a second activation signal associated with the first ED ona set of subcarriers of the second CC bandwidth, the second activationsignal indicating a start of second uplink transmission from the firstED on the set of subcarriers of the second CC bandwidth; and decodinguplink payload data for the first ED in response to detecting theactivation signal comprises at least one of: in response to detectingthe first activation signal associated with the first ED on the set ofsubcarriers of the first CC bandwidth, decoding first uplink payloaddata for the first ED received by the base station on the set ofsubcarriers of the first CC bandwidth between the start of first uplinktransmission from the first ED and the end of the allocatedtime-frequency resource; and in response to detecting the secondactivation signal associated with the first ED on the set of subcarriersof the second CC bandwidth, decoding second uplink payload data for thefirst ED received by the base station on the set of subcarriers of thesecond CC bandwidth between the start of second uplink transmission fromthe first ED and the end of the allocated time-frequency resource;

further comprising: transmitting a second uplink grant message for asecond ED, the second uplink grant message indicating the second ED isallocated the set of subcarriers of the second CC bandwidth within thetime-frequency resource for uplink transmission in the unlicensedspectrum band; monitoring for detection of an activation signalassociated with the second ED on the set of subcarriers of the second CCbandwidth at start times based on the start point configuration withinthe time-frequency resource until either the activation signalassociated with the second ED is detected or the time-frequency resourceends, the activation signal associated with the second ED indicating astart of uplink transmission from the second ED; and in response todetecting the activation signal associated with the second ED, decodinguplink payload data for the second ED received by the base station onthe set of subcarriers of the second CC bandwidth between the start ofuplink transmission from the second ED and the end of the time-frequencyresource.

FIGS. 10A and 10B illustrate example devices that may implement themethods and teachings according to this disclosure. In particular, FIG.10A illustrates an example ED 110, and FIG. 10B illustrates an examplebase station 170. These components could be used in the communicationsystem 100 or in any other suitable system.

As shown in FIG. 10A, the ED 110 includes at least one processing unit200. The processing unit 200 implements various processing operations ofthe ED 110. For example, the processing unit 200 could perform signalcoding, data processing, power control, input/output processing, or anyother functionality enabling the ED 110 to operate in the communicationsystem 100. The processing unit 200 may also be configured to implementsome or all of the functionality and/or embodiments described in moredetail above. Each processing unit 200 includes any suitable processingor computing device configured to perform one or more operations. Eachprocessing unit 200 could, for example, include a microprocessor,microcontroller, digital signal processor, field programmable gatearray, or application specific integrated circuit.

The ED 110 also includes at least one transceiver 202. The transceiver202 is configured to modulate data or other content for transmission byat least one antenna or Network Interface Controller (NIC) 204. Thetransceiver 202 is also configured to demodulate data or other contentreceived by the at least one antenna 204. Each transceiver 202 includesany suitable structure for generating signals for wireless or wiredtransmission and/or processing signals received wirelessly or by wire.Each antenna 204 includes any suitable structure for transmitting and/orreceiving wireless or wired signals. One or multiple transceivers 202could be used in the ED 110. One or multiple antennas 204 could be usedin the ED 110. Although shown as a single functional unit, a transceiver202 could also be implemented using at least one transmitter and atleast one separate receiver.

The ED 110 further includes one or more input/output devices 206 orinterfaces (such as a wired interface to the internet 150). Theinput/output devices 206 permit interaction with a user or other devicesin the network. Each input/output device 206 includes any suitablestructure for providing information to or receiving information from auser, such as a speaker, microphone, keypad, keyboard, display, or touchscreen, including network interface communications.

In addition, the ED 110 includes at least one memory 208. The memory 208stores instructions and data used, generated, or collected by the ED110. For example, the memory 208 could store software instructions ormodules configured to implement some or all of the functionality and/orembodiments described above and that are executed by the processingunit(s) 200. Each memory 208 includes any suitable volatile and/ornon-volatile storage and retrieval device(s). Any suitable type ofmemory may be used, such as random access memory (RAM), read only memory(ROM), hard disk, optical disc, subscriber identity module (SIM) card,memory stick, secure digital (SD) memory card, and the like.

As shown in FIG. 10B, the base station 170 includes at least oneprocessing unit 250, at least one transmitter 252, at least one receiver254, one or more antennas 256, at least one memory 258, and one or moreinput/output devices or interfaces 266. A transceiver, not shown, may beused instead of the transmitter 252 and receiver 254. A scheduler 253may be coupled to the processing unit 250. The scheduler 253 may beincluded within or operated separately from the base station 170. Theprocessing unit 250 implements various processing operations of the basestation 170, such as signal coding, data processing, power control,input/output processing, or any other functionality. The processing unit250 can also be configured to implement some or all of the functionalityand/or embodiments described in more detail above. Each processing unit250 includes any suitable processing or computing device configured toperform one or more operations. Each processing unit 250 could, forexample, include a microprocessor, microcontroller, digital signalprocessor, field programmable gate array, or application specificintegrated circuit.

Each transmitter 252 includes any suitable structure for generatingsignals for wireless or wired transmission to one or more EDs or otherdevices. Each receiver 254 includes any suitable structure forprocessing signals received wirelessly or by wire from one or more EDsor other devices. Although shown as separate components, at least onetransmitter 252 and at least one receiver 254 could be combined into atransceiver. Each antenna 256 includes any suitable structure fortransmitting and/or receiving wireless or wired signals. Although acommon antenna 256 is shown here as being coupled to both thetransmitter 252 and the receiver 254, one or more antennas 256 could becoupled to the transmitter(s) 252, and one or more separate antennas 256could be coupled to the receiver(s) 254. Each memory 258 includes anysuitable volatile and/or non-volatile storage and retrieval device(s)such as those described above in connection to the ED 110. The memory258 stores instructions and data used, generated, or collected by thebase station 170. For example, the memory 258 could store softwareinstructions or modules configured to implement some or all of thefunctionality and/or embodiments described above and that are executedby the processing unit(s) 250.

Each input/output device 266 permits interaction with a user or otherdevices in the network. Each input/output device 266 includes anysuitable structure for providing information to or receiving/providinginformation from a user, including network interface communications.

It should be appreciated that one or more steps of the embodimentmethods provided herein may be performed by corresponding units ormodules. For example, a signal may be transmitted by a transmitting unitor a transmitting module. A signal may be received by a receiving unitor a receiving module. A signal may be processed by a processing unit ora processing module. The respective units/modules may be hardware,software, or a combination thereof. For instance, one or more of theunits/modules may be an integrated circuit, such as field programmablegate arrays (FPGAs) or application-specific integrated circuits (ASICs).It will be appreciated that where the modules are software, they may beretrieved by a processor, in whole or part as needed, individually ortogether for processing, in single or multiple instances as required,and that the modules themselves may include instructions for furtherdeployment and instantiation.

Additional details regarding the EDs 110 and the base stations 170 areknown to those of skill in the art. As such, these details are omittedhere for clarity.

EXAMPLE EMBODIMENTS

The following provides a non-limiting list of Example Embodiments of thepresent disclosure:

Example Embodiment 1

A method for an Electronic Device (ED) in a wireless network, the methodcomprising:

-   -   receiving an uplink grant message from a base station, the        uplink grant message indicating a time-frequency resource        allocated to the ED for uplink transmission in an unlicensed        spectrum band;    -   performing a first listen-before-talk (LBT) operation for the        allocated time-frequency resource;    -   performing a second LBT operation within the allocated        time-frequency resource.

Example Embodiment 2

The method of Example Embodiment 1, further comprising:

-   -   in response to the second LBT operation succeeding, transmitting        an uplink transmission within a remaining portion of the        allocated time-frequency resource, the uplink transmission        comprising:    -   an activation signal to indicate a start of the uplink        transmission; and    -   uplink payload data.

Example Embodiment 3

The method of Example Embodiment 2, wherein the second LBT operation isperformed at a start time based on a start point configuration withinthe allocated time frequency resource.

Example Embodiment 4

The method of Example Embodiment 3, wherein the start pointconfiguration indicates the configuration of a plurality of possiblestart points of uplink transmission within a subframe.

Example Embodiment 5

The method of Example Embodiment 4, wherein each start point is eitherat an OFDM symbol boundary or midway between adjacent OFDM symbolboundaries, within the allocated time-frequency resource.

Example Embodiment 6

The method of Example Embodiment 3, further comprising receiving, fromthe base station, information indicating the start point configuration.

Example Embodiment 7

The method of Example Embodiment 2, wherein the activation signal is ademodulation reference signal (DMRS).

Example Embodiment 8

The method of Example Embodiment 3, wherein transmitting an uplinktransmission within the remaining portion of the allocatedtime-frequency resource comprises transmitting the uplink transmissionwith one or more blanking intervals within the remaining portion of theallocated time-frequency resource based on the start pointconfiguration.

Example Embodiment 9

The method of Example Embodiments 3, wherein performing a second LBToperation within the allocated time-frequency resource comprisesperforming an LBT operation at each of a plurality of start times basedon the start point configuration until one of the LBT operationssucceeds.

Example Embodiment 10

The method of Example Embodiment 1, wherein the second LBT operation isperformed during one or more orthogonal frequency division multiplexing(OFDM) symbol intervals immediately preceding a start point within theallocated time-frequency resource.

Example Embodiment 11

The method of Example Embodiment 10, further comprising, in response tothe second LBT operation succeeding, transmitting a reservation signalbetween the start point of uplink transmission and the closest OFDMsymbol boundary after the start point.

Example Embodiment 12

The method of Example Embodiment 11, wherein the reservation signalincludes a cyclic prefix extension of the following OFDM symbol.

Example Embodiment 13

The method of Example Embodiment 2, wherein transmitting an uplinktransmission within a remaining portion of the allocated time-frequencyresource comprises transmitting the activation signal at a start pointthat is part of a pre-configured subset of possible start points withinthe allocated time-frequency resource.

Example Embodiment 14

The method of Example Embodiment 13, wherein the pre-configured subsetof possible start points includes every second possible start point foruplink transmission within the allocated time-frequency resource.

Example Embodiment 15

The method of Example Embodiment 13, wherein the activation signal isselected by the ED from among a plurality of activation signalsassociated with the ED, the plurality of activation signals comprising:

-   -   a first activation signal to indicate that uplink transmission        started at a start point that preceded the start point at which        the first activation signal is transmitted; and    -   a second activation signal to indicate that uplink transmission        started at or after the start point at which the first        activation signal is transmitted.

Example Embodiment 16

The method of Example Embodiment 2, wherein the ED configures atransport block size for the uplink payload data based on a size of theremaining portion of the allocated time-frequency resource.

Example Embodiment 17

The method of Example Embodiment 16, wherein transmitting the uplinktransmission comprises:

-   -   using packet segmentation to generate the uplink payload data        based on the adjusted transport block size.

Example Embodiment 18

The method of Example Embodiment 16, wherein:

-   -   uplink transmissions for different transport block sizes        corresponding to different start points are generated in advance        of the first possible start point of uplink transmission for the        allocated time-frequency resource; and    -   transmitting the uplink transmission comprises transmitting the        uplink transmission for the transport block size corresponding        to the start point of the uplink transmission.

Example Embodiment 19

The method of Example Embodiment 2, wherein the ED uses rate matching orpuncturing to fit a transport block into the remaining portion of theallocated time-frequency resource without changing the transport blocksize.

Example Embodiment 20

The method of Example Embodiment 3, wherein:

-   -   the ED is allocated a subset of subcarriers of a component        carrier (CC) bandwidth;    -   the second LBT operation is a wideband LBT operation that is        based on energy measured on all of the subcarriers of the CC        bandwidth during one or more OFDM symbol intervals immediately        preceding a start point within the allocated time-frequency        resource; and    -   transmitting the uplink transmission comprises transmitting the        uplink transmission on the allocated subset of subcarriers        within the remaining portion of the allocated time-frequency        resource with one or more blanking intervals based on the start        point configuration.

Example Embodiment 21

The method of Example Embodiment 2, wherein:

-   -   the ED is allocated a subset of subcarriers of a component        carrier (CC) bandwidth;    -   the second LBT operation is a narrowband LBT operation that is        based on energy measured on the allocated subset of subcarriers        during one or more OFDM symbol intervals immediately preceding a        start point within the allocated time-frequency resource; and    -   transmitting the uplink transmission comprises transmitting the        uplink transmission on the allocated subset of subcarriers        within the remaining portion of the allocated time-frequency        resource.

Example Embodiment 22

The method of Example Embodiment 21, wherein the first LBT operation isa wideband LBT operation that is based on energy measured on all of thesubcarriers of the CC bandwidth during one or more OFDM symbol intervalsimmediately preceding or immediately after a sub-frame boundary of thetime-frequency resource.

Example Embodiment 23

The method of Example Embodiment 21, wherein the allocated subset ofsubcarriers correspond to the subcarriers of a physical resource block(PRB) within the allocated time-frequency resource.

Example Embodiment 24

The method of Example Embodiment 2, wherein:

-   -   the ED is allocated an interlace of a plurality of subsets of        subcarriers of the CC bandwidth, the subsets of subcarriers of        the interlace being distributed within the CC bandwidth;    -   the second LBT operation is one of a plurality of second LBT        operations that are respectively based on energy measured on a        respective one of the subsets of subcarriers of the CC bandwidth        during one or more OFDM symbol intervals immediately preceding        the start point within the allocated time-frequency resource;        and    -   transmitting the uplink transmission comprises transmitting,        within the remaining portion of the allocated time-frequency        resource, an uplink transmission on one or more of the allocated        subsets of subcarriers for which the respective narrowband LBT        procedure was successful.

Example Embodiment 25

The method of Example Embodiment 2, wherein transmitting an uplinktransmission comprises transmitting the activation signal and/or ademodulation reference signal on the first one or more OFDM symbolintervals after a start point within the remaining portion of theallocated time-frequency resource.

Example Embodiment 26

The method of Example Embodiment 2, wherein transmitting an uplinktransmission comprises:

-   -   transmitting the activation signal on the first one or more OFDM        symbol intervals of a first start point after the second LBT        operation is successful; and    -   transmitting a demodulation reference signal on the last one or        more OFDM symbol intervals of a subframe at the end of the        allocated time-frequency resource.

Example Embodiment 27

The method of Example Embodiment 26, wherein the activation signal issparse in the frequency domain.

Example Embodiment 28

The method of Example Embodiment 2 wherein:

-   -   the ED is allocated a set of subcarriers of a first component        carrier (CC) bandwidth;    -   the first and second LBT operations are based on energy measured        on the allocated set of subcarriers of the first CC bandwidth;    -   transmitting the uplink transmission comprises transmitting a        first uplink transmission on the allocated set of subcarriers of        the first CC bandwidth within a first remaining portion of the        allocated time-frequency resource;    -   the ED is allocated a set of subcarriers of a second CC        bandwidth that is non-overlapping with the first CC bandwidth;        and    -   the method further comprises performing LBT operations that are        based on energy measured on the allocated set of subcarriers of        the second CC bandwidth at the same time that the LBT operations        that are based on energy measured on the allocated set of        subcarriers of the first CC bandwidth are performed.

Example Embodiment 29

The method of Example Embodiment 28, further comprising:

-   -   continuing to perform LBT operations that are based on energy        measured on the allocated set of subcarriers of the second CC        bandwidth at subsequent start points within the allocated        time-frequency resource after the second LBT operation based on        energy measured on the allocated set of subcarriers of the first        CC bandwidth succeeds; and    -   in response to one of the LBT operations that are based on        energy measured on the allocated set of subcarriers of the first        CC bandwidth succeeding, transmitting a second uplink        transmission on the allocated set of subcarriers of the second        CC bandwidth within a second remaining portion of the allocated        time-frequency resource, the second uplink transmission        comprising:    -   a second activation signal to indicate a start of the second        uplink transmission; and    -   second uplink payload data.

Example Embodiment 30

The method of Example Embodiment 2, wherein:

-   -   there is a predefined mapping between code blocks of data and        start point within the allocated time-frequency resource; and    -   the uplink payload data that is transmitted as part of the        uplink transmission includes the code blocks of data that are        mapped to start points within the remaining portion of the        allocated time-frequency resource.

Example Embodiment 31

The method of Example Embodiment 2, wherein:

-   -   there is a predefined mapping between code blocks of data and        start points within the allocated time-frequency resource; and    -   the uplink payload data that is transmitted as part of the        uplink transmission includes a sequence of code blocks of data        starting with the code block mapped to a first start point of        the allocated time-frequency resource.

Example Embodiment 32

A method for a base station in a wireless network, the methodcomprising:

-   -   transmitting a first uplink grant message for a first electronic        device (ED), the first uplink grant message indicating a        time-frequency resource allocated to the first ED for uplink        transmission in an unlicensed spectrum band;    -   monitoring for detection of an activation signal associated with        the first ED at start times based on a start point configuration        within the allocated time-frequency resource until either the        activation signal associated with the first ED is detected or        the allocated time-frequency resource ends, the activation        signal associated with the first ED indicating a start of uplink        transmission from the first ED; and    -   in response to detecting the activation signal associated with        the first ED, decoding uplink payload data for the first ED        received by the base station between the start of uplink        transmission from the first ED and the end of the allocated        time-frequency resource.

Example Embodiment 33

The method of Example Embodiment 32, wherein the start pointconfiguration indicates the configuration of a plurality of start pointwithin a subframe.

Example Embodiment 34

The method of Example Embodiment 32, further comprising:

-   -   pre-configuring the start point configuration at the base        station; and    -   transmitting, from the base station, an information message        indicating the start point configuration.

Example Embodiment 35

The method of Example Embodiment 32, wherein the activation signal is ademodulation reference signal (DMRS) associated with the first ED andthe base station uses the DMRS to decode the uplink payload data for thefirst ED.

Example Embodiment 36

The method of Example Embodiment 32, wherein decoding uplink payloaddata for the first ED comprises decoding the uplink payload data takinginto account one or more blanking intervals within the remaining portionof the allocated time-frequency resource based on the mini-slotconfiguration.

Example Embodiment 37

The method of Example Embodiment 32, wherein monitoring for detection ofthe activation signal associated with the first ED comprises monitoringfor detection of the activation signal associated with the first EDstarting at or after each of a plurality of start points within theallocated time-frequency resource until either the activation signalassociated with the first ED is detected or the allocated time-frequencyresource ends.

Example Embodiment 38

The method of Example Embodiment 32, wherein monitoring for detection ofan activation signal associated with the first ED comprises monitoringfor detection of the activation signal at a pre-configured subset of thepossible start points for uplink transmission within the allocatedtime-frequency resource.

Example Embodiment 39

The method of Example Embodiment 38, wherein the pre-configured subsetof possible start points includes every second possible start point foruplink transmission within the allocated time-frequency resource.

Example Embodiment 40

The method of Example Embodiment 38, wherein monitoring for detection ofan activation signal associated with the first ED comprises monitoringfor detection of a plurality of activation signals associated with thefirst ED, the plurality of activation signals comprising:

-   -   a first activation signal to indicate that uplink transmission        started at a start point that preceded the start point at which        the first activation signal is transmitted; and    -   a second activation signal to indicate that uplink transmission        started at or after the start point at which the first        activation signal is transmitted.

Example Embodiment 41

The method of Example Embodiment 32, wherein decoding the uplink payloaddata for the first ED in response to detecting the activation signalindicating the start of uplink transmission from the first ED comprises:

-   -   determining an expected transport block size for the uplink        payload data based on a size of a remaining portion of the        allocated time-frequency resource after the start of uplink        transmission from the first ED; and    -   decoding the uplink payload data based in part on the expected        transport block size.

Example Embodiment 42

The method of Example Embodiment 41, wherein the base station determinesthe expected transport block size based on a mapping between transportblock sizes and possible start points for uplink transmission within theallocated time-frequency resource.

Example Embodiment 43

The method of Example Embodiment 32, wherein decoding the uplink payloaddata takes into account rate matching or puncturing done by the first EDto fit a transport block into the remaining portion of the allocatedtime-frequency resource.

Example Embodiment 44

The method of Example Embodiment 32, wherein:

-   -   the first uplink grant message for the first ED indicates the        first ED is allocated a first subset of subcarriers of a        component carrier (CC) bandwidth within the time-frequency        resource;    -   monitoring for detection of an activation signal associated with        the first ED comprises monitoring for the detection of the        activation signal associated with the first ED on the first        subset of subcarriers allocated to the first ED; and    -   decoding uplink payload data for the first ED in response to        detecting the activation signal associated with the first ED        comprises decoding the uplink payload data for the first ED        received by the base station on the first subset of subcarriers        allocated to the first ED between the start of uplink        transmission from the first ED and the end of the time-frequency        resource.

Example Embodiment 45

The method of Example Embodiment 44, further comprising:

-   -   transmitting a second uplink grant message for a second ED, the        second uplink grant message indicating the second ED is        allocated a second subset of subcarriers of the CC bandwidth        within the time-frequency resource for uplink transmission in        the unlicensed spectrum band, the second subset of subcarriers        being non-overlapping with the first subset of subcarriers;    -   monitoring for detection of an activation signal associated with        the second ED on the second subset of subcarriers at start times        based on the start point configuration within the time-frequency        resource until either the activation signal associated with the        second ED is detected or the time-frequency resource ends, the        activation signal associated with the second ED indicting a        start of uplink transmission from the second ED; and    -   in response to detecting the activation signal associated with        the second ED, decoding uplink payload data for the second ED        received by the base station on the second subset of subcarriers        between the start of uplink transmission from the second ED and        the end of the time-frequency resource.

Example Embodiment 46

The method of Example Embodiment 45, wherein the allocated subsets ofsubcarriers correspond to the subcarriers of first and second physicalresource blocks (PRBs), respectively, within the time-frequencyresource.

Example Embodiment 47

The method of Example Embodiment 32, wherein:

-   -   the first uplink grant message for the first ED indicates the        first ED is allocated a first interlace of a plurality of        subsets of subcarriers of a component carrier (CC) bandwidth        within the time-frequency resource, the subsets of subcarriers        of the first interlace being non-overlapping and distributed        within the CC bandwidth;    -   monitoring for detection of an activation signal associated with        the first ED comprises monitoring for the detection of the        activation signal associated with the first ED on each of the        subsets of subcarriers of the first interlace; and    -   decoding uplink payload data for the first ED in response to        detecting the activation signal associated with the first ED        comprises decoding uplink payload data for the first ED received        by the base station on one or more of the subsets of subcarriers        in the first interlace between the start of uplink transmission        from the first ED and the end of the time-frequency resource.

Example Embodiment 48

The method of Example Embodiment 47, further comprising:

-   -   transmitting a second uplink grant message for a second ED, the        second uplink grant message indicating the second ED is        allocated a second interlace of a plurality of subsets of        subcarriers of the CC bandwidth within the time-frequency        resource for uplink transmission in the unlicensed spectrum        band, the subsets of subcarriers of the second interlace being        distributed within the CC bandwidth such that the second        interlace is non-overlapping with the first interlace within the        CC bandwidth;    -   monitoring for detection of an activation signal associated with        the second ED on each of the subsets of subcarriers of the        second interlace at start times based on the start point        configuration within the time-frequency resource until either        the activation signal associated with the second ED is detected        or the time-frequency resource ends, the activation signal        associated with the second ED indicting a start of uplink        transmission from the second ED on the respective subset of        subcarriers on which the activation signal is transmitted; and    -   in response to detecting the activation signal associated with        the second ED, decoding uplink payload data for the second ED        received by the base station on one or more of the subsets of        subcarriers in the second interlace between the start of uplink        transmission from the second ED and the end of the        time-frequency resource.

Example Embodiment 49

The method of Example Embodiment 32, wherein the base station decodesthe uplink payload data for the first ED based in part on a demodulationreference signal transmitted by the first ED as part of the uplinktransmission on the first one or more OFDM symbol intervals of eachstart point between the start of uplink transmission from the first EDand the end of the allocated time-frequency resource.

Example Embodiment 50

The method of Example Embodiment 32, wherein the base station decodesthe uplink payload data for the first ED based in part on a demodulationreference signal transmitted by the first ED as part of the uplinktransmission on the last one or more OFDM symbol intervals of a subframeat the end of the allocated time-frequency resource.

Example Embodiment 51

The method of Example Embodiment 32, wherein:

-   -   the first uplink grant message for the first ED indicates the        first ED is allocated first and second component carrier (CC)        bandwidths within the time-frequency resource;    -   monitoring for detection of an activation signal associated with        the first ED comprises:    -   monitoring for detection of a first activation signal associated        with the first ED on a set of subcarriers of the first CC        bandwidth, the first activation signal indicating a start of        first uplink transmission from the first ED on the set of        subcarriers of the first CC bandwidth; and    -   monitoring for detection of a second activation signal        associated with the first ED on a set of subcarriers of the        second CC bandwidth, the second activation signal indicating a        start of second uplink transmission from the first ED on the set        of subcarriers of the second CC bandwidth; and    -   decoding uplink payload data for the first ED in response to        detecting the activation signal comprises at least one of:    -   in response to detecting the first activation signal associated        with the first ED on the set of subcarriers of the first CC        bandwidth, decoding first uplink payload data for the first ED        received by the base station on the set of subcarriers of the        first CC bandwidth between the start of first uplink        transmission from the first ED and the end of the allocated        time-frequency resource; and    -   in response to detecting the second activation signal associated        with the first ED on the set of subcarriers of the second CC        bandwidth, decoding second uplink payload data for the first ED        received by the base station on the set of subcarriers of the        second CC bandwidth between the start of second uplink        transmission from the first ED and the end of the allocated        time-frequency resource.

Example Embodiment 52

The method of Example Embodiment 51, further comprising:

-   -   transmitting a second uplink grant message for a second ED, the        second uplink grant message indicating the second ED is        allocated the set of subcarriers of the second CC bandwidth        within the time-frequency resource for uplink transmission in        the unlicensed spectrum band;    -   monitoring for detection of an activation signal associated with        the second ED on the set of subcarriers of the second CC        bandwidth at start times based on the start point configuration        within the time-frequency resource until either the activation        signal associated with the second ED is detected or the        time-frequency resource ends, the activation signal associated        with the second ED indicating a start of uplink transmission        from the second ED; and    -   in response to detecting the activation signal associated with        the second ED, decoding uplink payload data for the second ED        received by the base station on the set of subcarriers of the        second CC bandwidth between the start of uplink transmission        from the second ED and the end of the time-frequency resource.

Example Embodiment 53

An Electronic Device (ED) comprising:

-   -   one or more processors; and    -   a non-transitory computer readable storage medium storing        programming for execution by the one or more processors, the        programming including instructions to:    -   receive an uplink grant message from a base station, the uplink        grant message indicating a time-frequency resource allocated to        the ED for uplink transmission in an unlicensed spectrum band;    -   perform a first listen-before-talk (LBT) operation for the        allocated time-frequency resource; and    -   perform a second LBT operation within the allocated        time-frequency resource.

Example Embodiment 54

The ED of Example Embodiment 53, wherein the programming furthercomprises instructions to:

-   -   perform the second LBT operation at a start time based on a        start point configuration within the allocated time-frequency        resource; and    -   in response to the second LBT operation succeeding, transmit an        uplink transmission within a remaining portion of the allocated        time-frequency resource, the uplink transmission comprising: an        activation signal to indicate a start of the uplink        transmission; and uplink payload data.

Example Embodiment 55

The ED of Example Embodiment 54, wherein the start point configurationindicates the configuration of a plurality of possible start points ofuplink transmission within a subframe.

Example Embodiment 56

The ED of Example Embodiment 55, wherein each start point is either atan OFDM symbol boundary or midway between adjacent OFDM symbolboundaries, within the allocated time-frequency resource.

Example Embodiment 57

The ED of any one of Example Embodiments 54 to 56, wherein theprogramming further comprises instructions to receive, from the basestation, information indicating the start point configuration.

Example Embodiment 58

The ED of any one of Example Embodiments 54 to 57, wherein theactivation signal is a demodulation reference signal (DMRS).

Example Embodiment 59

The ED of any one of Example Embodiments 54 to 58, wherein theinstructions to transmit an uplink transmission within the remainingportion of the allocated time-frequency resource comprises instructionsto transmit the uplink transmission with one or more blanking intervalswithin the remaining portion of the allocated time-frequency resourcebased on the start point configuration.

Example Embodiment 60

The ED of any one of Example Embodiments 54 to 59, wherein theinstructions to perform a second LBT operation within the allocatedtime-frequency resource comprises instructions to perform an LBToperation at each of a plurality of start times based on the start pointconfiguration until one of the LBT operations succeeds.

Example Embodiment 61

The ED of any one of Example Embodiments 54 to 58, wherein the secondLBT operation is performed during one or more orthogonal frequencydivision multiplexing (OFDM) symbol intervals immediately preceding astart point within the allocated time-frequency resource.

Example Embodiment 62

The ED of any one of Example Embodiments 54 to 61, wherein theprogramming further comprises instructions to transmit a reservationsignal between the start point of uplink transmission and the closestOFDM symbol boundary after the start point, in response to the secondLBT operation succeeding.

Example Embodiment 63

The ED of Example Embodiment 62, wherein the reservation signal includesa cyclic prefix extension of the following OFDM symbol.

Example Embodiment 64

The ED of any one of Example Embodiments 54 to 63, wherein theinstructions to transmit an uplink transmission within a remainingportion of the allocated time-frequency resource comprises instructionsto transmit the activation signal at a start point that is part of apre-configured subset of possible start points within the allocatedtime-frequency resource.

Example Embodiment 65

The ED of Example Embodiment 64, wherein the pre-configured subset ofpossible start points includes every second possible start point foruplink transmission within the allocated time-frequency resource.

Example Embodiment 66

The ED of Example Embodiment 64 or 65, wherein the activation signal isselected by the ED from among a plurality of activation signalsassociated with the ED, the plurality of activation signals comprising:

a first activation signal to indicate that uplink transmission startedat a start point that preceded the start point at which the firstactivation signal is transmitted; and

a second activation signal to indicate that uplink transmission startedat or after the start point at which the first activation signal istransmitted.

Example Embodiment 67

The ED of any one of Example Embodiments 54 to 66, wherein theprogramming further comprises instructions to configure a transportblock size for the uplink payload data based on a size of the remainingportion of the allocated time-frequency resource.

Example Embodiment 68

The ED of Example Embodiment 67, wherein the instructions to transmitthe uplink transmission comprises instructions to use packetsegmentation to generate the uplink payload data based on the adjustedtransport block size.

Example Embodiment 69

The ED of Example Embodiment 57 or 58, wherein:

-   -   the programming further comprises instructions to generate, in        advance of the first possible start point of uplink transmission        for the allocated time-frequency resource, uplink transmissions        for different transport block sizes corresponding to different        start points; and    -   the instructions to transmit the uplink transmission comprises        instructions to transmit the uplink transmission for the        transport block size corresponding to the start point of the        uplink transmission.

Example Embodiment 70

The ED of any one of Example Embodiments 54 to 66, wherein theprogramming further comprises instructions to use rate matching orpuncturing to fit a transport block into the remaining portion of theallocated time-frequency resource without changing the transport blocksize.

Example Embodiment 71

The ED of any one of Example Embodiments 54 to 70, wherein:

-   -   the ED is allocated a subset of subcarriers of a component        carrier (CC) bandwidth;    -   the second LBT operation is a wideband LBT operation that is        based on energy measured on all of the subcarriers of the CC        bandwidth during one or more OFDM symbol intervals immediately        preceding a start point within the allocated time-frequency        resource; and    -   the instructions to transmit the uplink transmission comprises        instructions to transmit the uplink transmission on the        allocated subset of subcarriers within the remaining portion of        the allocated time-frequency resource with one or more blanking        intervals based on the start point configuration.

Example Embodiment 72

The ED of any one of Example Embodiments 54 to 70, wherein:

-   -   the ED is allocated a subset of subcarriers of a component        carrier (CC) bandwidth;    -   the second LBT operation is a narrowband LBT operation that is        based on energy measured on the allocated subset of subcarriers        during one or more OFDM symbol intervals immediately preceding a        start point within the allocated time-frequency resource; and    -   the instructions to transmit the uplink transmission comprises        instructions to transmit the uplink transmission on the        allocated subset of subcarriers within the remaining portion of        the allocated time-frequency resource.

Example Embodiment 73

The ED of Example Embodiment 71 or 72, wherein the first LBT operationis a wideband LBT operation that is based on energy measured on all ofthe subcarriers of the CC bandwidth during one or more OFDM symbolintervals immediately preceding or immediately after a sub-frameboundary of the time-frequency resource.

Example Embodiment 74

The ED of any one of Example Embodiments 71 to 73, wherein the allocatedsubset of subcarriers correspond to the subcarriers of a physicalresource block (PRB) within the allocated time-frequency resource.

Example Embodiment 75

The ED of any one of Example Embodiments 71 to 74, wherein:

-   -   the ED is allocated an interlace of a plurality of subsets of        subcarriers of the CC bandwidth, the subsets of subcarriers of        the interlace being distributed within the CC bandwidth;    -   the second LBT operation is one of a plurality of second LBT        operations that are respectively based on energy measured on a        respective one of the subsets of subcarriers of the CC bandwidth        during one or more OFDM symbol intervals immediately preceding        the start point within the allocated time-frequency resource;        and    -   the instructions to transmit the uplink transmission comprises        instructions to transmit, within the remaining portion of the        allocated time-frequency resource, an uplink transmission on one        or more of the allocated subsets of subcarriers for which the        respective narrowband LBT procedure was successful.

Example Embodiment 76

The ED of any one of Example Embodiments 54 to 70, wherein theinstructions to transmit the uplink transmission comprises instructionsto transmit the activation signal and/or a demodulation reference signalon the first one or more OFDM symbol intervals after a start pointwithin the remaining portion of the allocated time-frequency resource.

Example Embodiment 77

The ED of any one of Example Embodiments 54 to 70, wherein theinstructions to transmit the uplink transmission comprises instructionsto:

-   -   transmit the activation signal on the first one or more OFDM        symbol intervals of a first start point after the second LBT        operation is successful; and    -   transmit a demodulation reference signal on the last one or more        OFDM symbol intervals of a subframe at the end of the allocated        time-frequency resource.

Example Embodiment 78

The ED of Example Embodiment 77, wherein the activation signal is sparsein the frequency domain.

Example Embodiment 79

The ED of any one of Example Embodiments 54 to 70 wherein:

-   -   the ED is allocated a set of subcarriers of a first component        carrier (CC) bandwidth;    -   the first and second LBT operations are based on energy measured        on the allocated set of subcarriers of the first CC bandwidth;    -   the instructions to transmit the uplink transmission comprises        instructions to transmit a first uplink transmission on the        allocated set of subcarriers of the first CC bandwidth within a        first remaining portion of the allocated time-frequency        resource;    -   the ED is allocated a set of subcarriers of a second CC        bandwidth that is non-overlapping with the first CC bandwidth;        and    -   the programming further comprises instructions to perform LBT        operations that are based on energy measured on the allocated        set of subcarriers of the second CC bandwidth at the same time        that the LBT operations that are based on energy measured on the        allocated set of subcarriers of the first CC bandwidth are        performed.

Example Embodiment 80

The ED of Example Embodiment 79, wherein the programming furthercomprises instructions to:

-   -   continue to perform LBT operations that are based on energy        measured on the allocated set of subcarriers of the second CC        bandwidth at subsequent start points within the allocated        time-frequency resource after the second LBT operation based on        energy measured on the allocated set of subcarriers of the first        CC bandwidth succeeds; and    -   in response to one of the LBT operations that are based on        energy measured on the allocated set of subcarriers of the first        CC bandwidth succeeding, transmit a second uplink transmission        on the allocated set of subcarriers of the second CC bandwidth        within a second remaining portion of the allocated        time-frequency resource, the second uplink transmission        comprising:    -   a second activation signal to indicate a start of the second        uplink transmission; and    -   second uplink payload data.

Example Embodiment 81

The ED of any one of Example Embodiments 54 to 80, wherein:

-   -   there is a predefined mapping between code blocks of data and        start point within the allocated time-frequency resource; and    -   the uplink payload data that is transmitted as part of the        uplink transmission includes the code blocks of data that are        mapped to start points within the remaining portion of the        allocated time-frequency resource.

Example Embodiment 82

The ED of any one of Example Embodiments 54 to 80, wherein:

-   -   there is a predefined mapping between code blocks of data and        start points within the allocated time-frequency resource; and    -   the uplink payload data that is transmitted as part of the        uplink transmission includes a sequence of code blocks of data        starting with the code block mapped to the first start point of        the allocated time-frequency resource.

Example Embodiment 83

A base station comprising:

-   -   one or more processors; and    -   a non-transitory computer readable storage medium storing        programming for execution by the one or more processors, the        programming including instructions to:    -   transmit a first uplink grant message for a first electronic        device (ED), the first uplink grant message indicating a        time-frequency resource allocated to the first ED for uplink        transmission in an unlicensed spectrum band;    -   monitor for detection of an activation signal associated with        the first ED at start times based on a start point configuration        within the allocated time-frequency resource until either the        activation signal associated with the first ED is detected or        the allocated time-frequency resource ends, the activation        signal associated with the first ED indicating a start of uplink        transmission from the first ED; and    -   in response to detecting the activation signal associated with        the first ED, decode uplink payload data for the first ED        received by the base station between the start of uplink        transmission from the first ED and the end of the allocated        time-frequency resource.

Example Embodiment 84

The base station of Example Embodiment 83, wherein the start pointconfiguration indicates the configuration of a plurality of start pointwithin a subframe.

Example Embodiment 85

The base station of Example Embodiment 83 or 84, wherein the programmingfurther comprises instructions to:

-   -   pre-configure the start point configuration at the base station;        and    -   transmit, from the base station, an information message        indicating the start point configuration.

Example Embodiment 86

The base station of any one of Example Embodiments 83 to 85, wherein theactivation signal is a demodulation reference signal (DMRS) associatedwith the first ED and the base station uses the DMRS to decode theuplink payload data for the first ED.

Example Embodiment 87

The base station of any one of Example Embodiments 83 to 86, wherein theinstructions to decode uplink payload data for the first ED comprisesinstructions to decode the uplink payload data taking into account oneor more blanking intervals within the remaining portion of the allocatedtime-frequency resource based on the mini-slot configuration.

Example Embodiment 88

The base station of any one of Example Embodiments 83 to 87, wherein theinstructions to monitor for detection of the activation signalassociated with the first ED comprises instruction to monitor fordetection of the activation signal associated with the first ED startingat or after each of a plurality of start points within the allocatedtime-frequency resource until either the activation signal associatedwith the first ED is detected or the allocated time-frequency resourceends.

Example Embodiment 89

The base station of any one of Example Embodiments 83 to 88, wherein theinstructions to monitor for detection of an activation signal associatedwith the first ED comprises instructions to monitor for detection of theactivation signal at a pre-configured subset of the possible startpoints for uplink transmission within the allocated time-frequencyresource.

Example Embodiment 90

The base station of Example Embodiment 89, wherein the pre-configuredsubset of possible start points includes every second possible startpoint for uplink transmission within the allocated time-frequencyresource.

Example Embodiment 91

The base station of Example Embodiment 89 or 90 wherein the instructionsto monitor for detection of an activation signal associated with thefirst ED comprises instructions to monitor for detection of a pluralityof activation signals associated with the first ED, the plurality ofactivation signals comprising:

-   -   a first activation signal to indicate that uplink transmission        started at a start point that preceded the start point at which        the first activation signal is transmitted; and    -   a second activation signal to indicate that uplink transmission        started at or after the start point at which the first        activation signal is transmitted.

Example Embodiment 92

The base station of any one of Example Embodiments 83 to 91, wherein theinstructions to decode the uplink payload data for the first ED inresponse to detecting the activation signal indicating the start ofuplink transmission from the first ED comprises instructions to:

-   -   determine an expected transport block size for the uplink        payload data based on a size of a remaining portion of the        allocated time-frequency resource after the start of uplink        transmission from the first ED; and    -   decode the uplink payload data based in part on the expected        transport block size.

Example Embodiment 93

The base station of Example Embodiment 92, wherein the instructions todetermine the expected transport block size comprises instructions todetermine the expected transport block size based on a mapping betweentransport block sizes and possible start points for uplink transmissionwithin the allocated time-frequency resource.

Example Embodiment 94

The base station of any one of Example Embodiments 83 to 91, wherein theinstructions to decode the uplink payload data take into account ratematching or puncturing done by the first ED to fit a transport blockinto the remaining portion of the allocated time-frequency resource.

Example Embodiment 95

The base station of any one of Example Embodiments 83 to 94, wherein:

-   -   the first uplink grant message for the first ED indicates the        first ED is allocated a first subset of subcarriers of a        component carrier (CC) bandwidth within the time-frequency        resource;    -   the instructions to monitor for detection of an activation        signal associated with the first ED comprises instructions to        monitor for the detection of the activation signal associated        with the first ED on the first subset of subcarriers allocated        to the first ED; and    -   the instructions to decode uplink payload data for the first ED        in response to detecting the activation signal associated with        the first ED comprises instructions to decode the uplink payload        data for the first ED received by the base station on the first        subset of subcarriers allocated to the first ED between the        start of uplink transmission from the first ED and the end of        the time-frequency resource.

Example Embodiment 96

The base station of Example Embodiment 95, wherein the programmingfurther comprises instructions to:

-   -   transmit a second uplink grant message for a second ED, the        second uplink grant message indicating the second ED is        allocated a second subset of subcarriers of the CC bandwidth        within the time-frequency resource for uplink transmission in        the unlicensed spectrum band, the second subset of subcarriers        being non-overlapping with the first subset of subcarriers;    -   monitor for detection of an activation signal associated with        the second ED on the second subset of subcarriers at start times        based on the start point configuration within the time-frequency        resource until either the activation signal associated with the        second ED is detected or the time-frequency resource ends, the        activation signal associated with the second ED indicting a        start of uplink transmission from the second ED; and    -   in response to detecting the activation signal associated with        the second ED, decode uplink payload data for the second ED        received by the base station on the second subset of subcarriers        between the start of uplink transmission from the second ED and        the end of the time-frequency resource.

Example Embodiment 97

The base station of Example Embodiment 96, wherein the allocated subsetsof subcarriers correspond to the subcarriers of first and secondphysical resource blocks (PRBs), respectively, within the time-frequencyresource.

Example Embodiment 98

The base station of any one of Example Embodiments 83 to 94, wherein:

-   -   the first uplink grant message for the first ED indicates the        first ED is allocated a first interlace of a plurality of        subsets of subcarriers of a component carrier (CC) bandwidth        within the time-frequency resource, the subsets of subcarriers        of the first interlace being non-overlapping and distributed        within the CC bandwidth;    -   the instructions to monitor for detection of an activation        signal associated with the first ED comprises instructions to        monitor for the detection of the activation signal associated        with the first ED on each of the subsets of subcarriers of the        first interlace; and    -   the instructions to decode uplink payload data for the first ED        in response to detecting the activation signal associated with        the first ED comprises instructions to decode uplink payload        data for the first ED received by the base station on one or        more of the subsets of subcarriers in the first interlace        between the start of uplink transmission from the first ED and        the end of the time-frequency resource.

Example Embodiment 99

The base station of Example Embodiment 98, wherein the programmingfurther comprises instructions to:

-   -   transmit a second uplink grant message for a second ED, the        second uplink grant message indicating the second ED is        allocated a second interlace of a plurality of subsets of        subcarriers of the CC bandwidth within the time-frequency        resource for uplink transmission in the unlicensed spectrum        band, the subsets of subcarriers of the second interlace being        distributed within the CC bandwidth such that the second        interlace is non-overlapping with the first interlace within the        CC bandwidth;    -   monitor for detection of an activation signal associated with        the second ED on each of the subsets of subcarriers of the        second interlace at start times based on the start point        configuration within the time-frequency resource until either        the activation signal associated with the second ED is detected        or the time-frequency resource ends, the activation signal        associated with the second ED indicting a start of uplink        transmission from the second ED on the respective subset of        subcarriers on which the activation signal is transmitted; and    -   in response to detecting the activation signal associated with        the second ED, decode uplink payload data for the second ED        received by the base station on one or more of the subsets of        subcarriers in the second interlace between the start of uplink        transmission from the second ED and the end of the        time-frequency resource.

Example Embodiment 100

The base station of any one of Example Embodiments 83 to 94, wherein theinstructions to decode the uplink payload data comprises instructions todecode the uplink payload data for the first ED based in part on ademodulation reference signal transmitted by the first ED as part of theuplink transmission on the first one or more OFDM symbol intervals ofeach start point between the start of uplink transmission from the firstED and the end of the allocated time-frequency resource.

Example Embodiment 101

The base station of any one of Example Embodiments 83 to 94, wherein theinstructions to decode the uplink payload data comprises instructions todecode the uplink payload data for the first ED based in part on ademodulation reference signal transmitted by the first ED as part of theuplink transmission on the last one or more OFDM symbol intervals of asubframe at the end of the allocated time-frequency resource.

Example Embodiment 102

The base station of any one of Example Embodiments 83 to 94, wherein:

-   -   the first uplink grant message for the first ED indicates the        first ED is allocated first and second component carrier (CC)        bandwidths within the time-frequency resource;    -   the instructions to monitor for detection of an activation        signal associated with the first ED comprises instructions to:    -   monitor for detection of a first activation signal associated        with the first ED on a set of subcarriers of the first CC        bandwidth, the first activation signal indicating a start of        first uplink transmission from the first ED on the set of        subcarriers of the first CC bandwidth; and    -   monitor for detection of a second activation signal associated        with the first ED on a set of subcarriers of the second CC        bandwidth, the second activation signal indicating a start of        second uplink transmission from the first ED on the set of        subcarriers of the second CC bandwidth; and    -   the instructions to decode uplink payload data for the first ED        in response to detecting the activation signal comprises at        least one of:    -   instructions to decode, in response to detecting the first        activation signal associated with the first ED on the set of        subcarriers of the first CC bandwidth, first uplink payload data        for the first ED received by the base station on the set of        subcarriers of the first CC bandwidth between the start of first        uplink transmission from the first ED and the end of the        allocated time-frequency resource; and    -   instructions to decode, in response to detecting the second        activation signal associated with the first ED on the set of        subcarriers of the second CC bandwidth, second uplink payload        data for the first ED received by the base station on the set of        subcarriers of the second CC bandwidth between the start of        second uplink transmission from the first ED and the end of the        allocated time-frequency resource.

Example Embodiment 103

The base station of Example Embodiment 102, wherein the programmingfurther comprises instructions to:

-   -   transmit a second uplink grant message for a second ED, the        second uplink grant message indicating the second ED is        allocated the set of subcarriers of the second CC bandwidth        within the time-frequency resource for uplink transmission in        the unlicensed spectrum band;    -   monitor for detection of an activation signal associated with        the second ED on the set of subcarriers of the second CC        bandwidth at start times based on the start point configuration        within the time-frequency resource until either the activation        signal associated with the second ED is detected or the        time-frequency resource ends, the activation signal associated        with the second ED indicating a start of uplink transmission        from the second ED; and    -   in response to detecting the activation signal associated with        the second ED, decode uplink payload data for the second ED        received by the base station on the set of subcarriers of the        second CC bandwidth between the start of uplink transmission        from the second ED and the end of the time-frequency resource.

In the preceding description, for purposes of explanation, numerousdetails are set forth in order to provide a thorough understanding ofthe embodiments. However, it will be apparent to one skilled in the artthat these specific details are not required. In other instances,well-known electrical structures and circuits are shown in block diagramform in order not to obscure the understanding. For example, specificdetails are not provided as to whether the embodiments described hereinare implemented as a software routine, hardware circuit, firmware, or acombination thereof.

Embodiments of the disclosure can be represented as a computer programproduct stored in a machine-readable medium (also referred to as acomputer-readable medium, a processor-readable medium, or a computerusable medium having a computer-readable program code embodied therein).The machine-readable medium can be any suitable tangible, non-transitorymedium, including magnetic, optical, or electrical storage mediumincluding a diskette, compact disk read only memory (CD-ROM), memorydevice (volatile or non-volatile), or similar storage mechanism. Themachine-readable medium can contain various sets of instructions, codesequences, configuration information, or other data, which, whenexecuted, cause a processor to perform steps in a method according to anembodiment of the disclosure. Those of ordinary skill in the art willappreciate that other instructions and operations necessary to implementthe described implementations can also be stored on the machine-readablemedium. The instructions stored on the machine-readable medium can beexecuted by a processor or other suitable processing device, and caninterface with circuitry to perform the described tasks.

The contents of the drawings are intended solely for illustrativepurposes, and the present invention is in no way limited to theparticular example embodiments explicitly shown in the drawings anddescribed herein. For example, FIG. 1 is a block diagram of acommunication system in which embodiments may be implemented. Otherembodiments could be implemented in communication systems that includemore network elements than shown, or that have different topologies thanthe example shown. Similarly, the examples in the other figures are alsointended solely for illustrative purposes.

Other implementation details could also vary between differentembodiments. For example, some of the examples above refer to LTEterminology. However, the embodiments disclosed herein are not in anyway limited to LTE systems.

In addition, although described primarily in the context of methods andsystems, other implementations are also contemplated, as instructionsstored on a non-transitory processor-readable medium, for example. Theinstructions, when executed by one or more processors, cause the one ormore processors to perform a method.

The above-described embodiments are intended to be examples only.Alterations, modifications and variations can be effected to theparticular embodiments by those of skill in the art. The scope of theclaims should not be limited by the particular embodiments set forthherein, but should be construed in a manner consistent with thespecification as a whole.

We claim:
 1. A method for an Electronic Device (ED) in a wirelessnetwork, the method comprising: receiving an uplink grant message from abase station, the uplink grant message indicating a time-frequencyresource allocated to the ED for uplink transmission in an unlicensedspectrum band; performing a first listen-before-talk (LBT) operation forthe allocated time-frequency resource; performing a second LBT operationwithin the allocated time-frequency resource; and in response to thesecond LBT operation succeeding, transmitting an uplink transmissionwithin a remaining portion of the allocated time-frequency resource, theuplink transmission comprising uplink payload data an activation signalto indicate a start of the uplink transmission, wherein the ED isallocated a subset of subcarriers of a component carrier (CC) bandwidth,wherein the second LBT operation is a narrowband LBT operation that isbased on energy measured on the allocated subset of subcarriers duringone or more OFDM symbol intervals immediately preceding a start pointwithin the allocated time-frequency resource, and wherein transmittingthe uplink transmission comprises transmitting the uplink transmissionon the allocated subset of subcarriers within the remaining portion ofthe allocated time-frequency resource.
 2. The method of claim 1, whereinthe start point is determined based on a start point configurationwithin the allocated time-frequency resource.
 3. The method of claim 2,wherein the start point configuration indicates a plurality of possiblestart points of uplink transmission within a subframe.
 4. The method ofclaim 3, wherein each start point is either at an OFDM symbol boundaryor midway between adjacent OFDM symbol boundaries, within the allocatedtime-frequency resource.
 5. The method of claim 2, further comprisingreceiving, from the base station, information indicating the start pointconfiguration.
 6. The method of claim 2, wherein transmitting an uplinktransmission within the remaining portion of the allocatedtime-frequency resource comprises transmitting the uplink transmissionwith one or more blanking intervals within the remaining portion of theallocated time-frequency resource based on the start pointconfiguration.
 7. The method of claim 2, wherein performing a second LBToperation within the allocated time-frequency resource comprisesperforming an LBT operation at each of a plurality of start times basedon the start point configuration until one of the LBT operationssucceeds.
 8. The method of claim 1, wherein the activation signal is ademodulation reference signal (DMRS).
 9. The method of claim 1, whereinthe second LBT operation is performed during one or more orthogonalfrequency division multiplexing (OFDM) symbol intervals immediatelypreceding a start point within the allocated time-frequency resource.10. The method of claim 9, further comprising, in response to the secondLBT operation succeeding, transmitting a reservation signal between thestart point and the closest OFDM symbol boundary after the start point.11. The method of claim 10, wherein the reservation signal includes acyclic prefix extension of the following OFDM symbol.
 12. The method ofclaim 1, wherein transmitting an uplink transmission within a remainingportion of the allocated time-frequency resource comprises transmittingthe activation signal at a start point that is part of a pre-configuredsubset of possible start points within the allocated time-frequencyresource.
 13. The method of claim 12, wherein the activation signal isselected by the ED from among a plurality of activation signalsassociated with the ED, the plurality of activation signals comprising:a first activation signal to indicate that uplink transmission startedat a start point that preceded the start point at which the firstactivation signal is transmitted; and a second activation signal toindicate that uplink transmission started at or after the start point atwhich the first activation signal is transmitted.
 14. The method ofclaim 1, wherein the first LBT operation is a wideband LBT operationthat is based on energy measured on all of the subcarriers of the CCbandwidth during one or more OFDM symbol intervals immediately precedingor immediately after a sub-frame boundary of the time-frequencyresource.
 15. An Electronic Device (ED) comprising: one or moreprocessors; and a non-transitory computer readable storage mediumstoring programming for execution by the one or more processors, theprogramming including instructions to: receive an uplink grant messagefrom a base station, the uplink grant message indicating atime-frequency resource allocated to the ED for uplink transmission inan unlicensed spectrum band; perform a first listen-before-talk (LBT)operation for the allocated time-frequency resource; perform a secondLBT operation within the allocated time-frequency resource; perform thesecond LBT operation at a start time based on a start pointconfiguration within the allocated time-frequency resource; and inresponse to the second LBT operation succeeding, transmit an uplinktransmission within a remaining portion of the allocated time-frequencyresource, the uplink transmission comprising uplink payload data and anactivation signal to indicate a start of the uplink transmission,wherein the ED is allocated a subset of subcarriers of a componentcarrier (CC) bandwidth, wherein the second LBT operation is a narrowbandLBT operation that is based on energy measured on the allocated subsetof subcarriers during one or more OFDM symbol intervals immediatelypreceding a start point within the allocated time-frequency resource,and wherein the instructions to transmit the uplink transmissioncomprises instructions to transmit the uplink transmission on theallocated subset of subcarriers within the remaining portion of theallocated time-frequency resource.
 16. The ED of claim 15, wherein thestart point configuration indicates a plurality of possible start pointsof uplink transmission within a subframe.
 17. The ED of claim 16,wherein each start point is either at an OFDM symbol boundary or midwaybetween adjacent OFDM symbol boundaries, within the allocatedtime-frequency resource.
 18. The ED of claim 15, wherein theinstructions to perform a second LBT operation within the allocatedtime-frequency resource comprises instructions to perform an LBToperation at each of a plurality of start times based on the start pointconfiguration until one of the LBT operations succeeds.
 19. The ED ofclaim 15, wherein the instructions to transmit an uplink transmissionwithin a remaining portion of the allocated time-frequency resourcecomprises instructions to transmit the activation signal at a startpoint that is part of a pre-configured subset of possible start pointswithin the allocated time-frequency resource.
 20. The ED of claim 19,wherein the activation signal is selected by the ED from among aplurality of activation signals associated with the ED, the plurality ofactivation signals comprising: a first activation signal to indicatethat uplink transmission started at a start point that preceded thestart point at which the first activation signal is transmitted; and asecond activation signal to indicate that uplink transmission started ator after the start point at which the first activation signal istransmitted.